U.S. patent application number 14/263870 was filed with the patent office on 2014-10-30 for low loss impedance transformers implemented as integrated passive devices and related methods thereof.
The applicant listed for this patent is SKYWORKS SOLUTIONS, INC.. Invention is credited to Aleksey A. LYALIN, Russ Alan REISNER, Weimin SUN.
Application Number | 20140320252 14/263870 |
Document ID | / |
Family ID | 51788747 |
Filed Date | 2014-10-30 |
United States Patent
Application |
20140320252 |
Kind Code |
A1 |
SUN; Weimin ; et
al. |
October 30, 2014 |
LOW LOSS IMPEDANCE TRANSFORMERS IMPLEMENTED AS INTEGRATED PASSIVE
DEVICES AND RELATED METHODS THEREOF
Abstract
Disclosed are apparatus and methods related to low loss
impedance transformers implemented as integrated passive devices
(IPDs). In some embodiments, an IPD can include an autotransformer
implemented within a body. The autotransformer can include primary
and secondary metal traces implemented in respective planes
separated by a distance. The autotransformer can be configured to,
for example, facilitate impedance matching of radio-frequency (RF)
signals. In some embodiments, the IPD can include a surface that
allows mounting of one or more components thereon to provide space
savings in RF modules. Examples of fabrication methods as well as
products that can benefit from such IPDs are disclosed.
Inventors: |
SUN; Weimin; (Santa Rosa
Valley, CA) ; LYALIN; Aleksey A.; (Thousand Oaks,
CA) ; REISNER; Russ Alan; (Newbury Park, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SKYWORKS SOLUTIONS, INC. |
Woburn |
MA |
US |
|
|
Family ID: |
51788747 |
Appl. No.: |
14/263870 |
Filed: |
April 28, 2014 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61817291 |
Apr 29, 2013 |
|
|
|
Current U.S.
Class: |
336/200 ;
29/602.1 |
Current CPC
Class: |
H03F 3/191 20130101;
H01L 2224/49171 20130101; H03F 2200/387 20130101; H03H 7/38
20130101; H01L 28/10 20130101; H01L 23/66 20130101; H01F 30/02
20130101; H03H 2001/0064 20130101; H03H 2001/0078 20130101; H01F
41/02 20130101; H03H 7/175 20130101; H01F 2027/2809 20130101; H03F
3/195 20130101; H03F 2200/391 20130101; H01F 27/2804 20130101; H03H
7/1758 20130101; H03H 7/1775 20130101; H01L 2223/6655 20130101;
H01L 2223/6672 20130101; H03F 1/565 20130101; Y10T 29/4902
20150115 |
Class at
Publication: |
336/200 ;
29/602.1 |
International
Class: |
H01F 27/28 20060101
H01F027/28; H01F 41/02 20060101 H01F041/02 |
Claims
1. An integrated passive device (IPD) comprising: a body; an
autotransformer implemented within the body, the autotransformer
including a primary metal trace having one or more turns between a
first end and a second end, the first end of the primary metal
trace defining a first node, the second end of the primary metal
trace defining a tap node, the autotransformer further including a
secondary metal trace having one or more turns between a first end
and a second end, the first end of the secondary metal trace
connected to the tap node, the second end of the secondary metal
trace defining a second node, the primary metal trace and the
secondary metal trace being in respective planes separated by a
distance; and a plurality of contact features implemented to
provide electrical connections between the autotransformer and a
first substrate.
2. The IPD of claim 1 wherein the body includes a substrate
configured to support the second metal trace.
3. The IPD of claim 2 wherein the body includes a surface defined
by a side of the substrate opposite from a side on which the
secondary metal trace is implemented on.
4. The IPD of claim 3 wherein the surface includes a substantially
flat surface that allows mounting of one or more components
thereon.
5. The IPD of claim 2 further comprising an insulator layer
implemented between the primary metal trace and the secondary metal
trace, the insulator layer having a thickness selected to provide
the separation distance.
6. The IPD of claim 5 further comprising one or more conductive
features implemented through the insulator layer, the conductive
feature configured to provide one or more electrical connections
between the primary metal trace and the secondary metal trace.
7. The IPD of claim 5 wherein the insulator layer includes a
dielectric material.
8. The IPD of claim 7 wherein the dielectric material includes
benzocyclobutene (BCB), polyimide, SiN (silicon nitride), or SiO2
(silicon dioxide).
9. The IPD of claim 2 further comprising one or more circuit
elements configured to provide matching functionality on either or
both sides of the autotransformer.
10. The IPD of claim 9 wherein the IPD is an impedance matching
device configured to match impedance for an output of a power
amplifier (PA).
11. A method for fabricating an integrated passive device (IPD),
the method comprising: providing or forming each of a first
substrate and a second substrate; implementing a primary metal
trace on the first substrate, the primary metal trace having one or
more turns between a first end and a second end; implementing a
secondary metal trace on the second substrate, the secondary metal
trace having one or more turns between a first end and a second
end; and flip-mounting the second substrate on the first substrate
to provide a desired separation distance between the primary metal
trace and the secondary metal trace, the flip-mounting including
formation of one or more electrical connections between the primary
metal trace and the secondary metal trace to form an
autotransformer.
12. The method of claim 11 further comprising forming an insulator
layer between the primary metal trace and the secondary metal
trace.
13. A radio-frequency (RF) module comprising: a packaging substrate
configured to receive a plurality of components; a power amplifier
(PA) die implemented on the packaging substrate, the PA die
including an output node configured to provide an amplified RF
signal; and an integrated passive device (IPD) implemented on the
packaging substrate, the IPD configured to receive the amplified RF
signal from the PA die, the IPD including a body, the IPD further
including an autotransformer implemented within the body, the
autotransformer configured to facilitate impedance matching of the
amplified RF signal; and a plurality of contact features
implemented to provide electrical connections between the
autotransformer and the packaging substrate.
14. The RF module of claim 13 wherein the packaging substrate is
configured to support a primary metal trace of the autotransformer,
and the body includes a die substrate configured to support a
secondary metal trace of the autotransformer.
15. The RF module of claim 14 wherein the die substrate is in a
flip-mounted configuration with respect to the packaging substrate
to provide the separation distance between the primary metal trace
and the secondary metal trace.
16. The RF module of claim 15 wherein the body includes a surface
defined by a side of the die substrate opposite from a side on
which the secondary metal trace is implemented on.
17. The RF module of claim 16 further comprising a component
mounted on the surface of the body in a stacked configuration.
18. The RF module of claim 17 wherein the stack configuration
allows a reduction in lateral size of the RF module.
19. The RF module of claim 13 wherein the packaging substrate
includes a laminate substrate.
20. The RF module of claim 19 wherein the IPD having the
autotransformer allows the laminate substrate to have a reduced
number of layers.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional
Application No. 61/817,291 filed Apr. 29, 2013, entitled DEVICES
AND METHODS RELATED TO AUTOTRANSFORMERS FOR RADIO-FREQUENCY
MATCHING CIRCUITS, the disclosure of which is hereby expressly
incorporated by reference herein in its entirety.
BACKGROUND
[0002] 1. Field
[0003] The present disclosure generally relates to
autotransformer-based impedance matching circuits implemented as
integrated passive devices (IPDs).
[0004] 2. Description of the Related Art
[0005] In radio-frequency (RF) applications, an impedance matching
circuit is typically implemented between an output of a power
amplifier (PA) and a circuit downstream of the output. Such a
downstream circuit can include, for example, a switching circuit, a
filter, a duplexer, etc., and be configured to route and/or
condition the amplified RF signal for transmission. The impedance
matching circuit is typically configured to provide transformation
of impedance between the PA and the downstream circuit to thereby
reduce loss of the amplified RF signal and to allow transmission of
the RF signal in an efficient manner.
SUMMARY
[0006] In some implementations, the present disclosure relates to
an impedance matching device for a radio-frequency (RF) power
amplifier (PA). The impedance matching device includes a primary
metal trace having one or more turns between a first end and a
second end. The first end of the primary metal trace is configured
to be capable of being connected to a voltage source for the PA.
The second end of the primary metal trace is configured to be
capable of being connected to an output of the PA. The impedance
matching device further includes a secondary metal trace having one
or more turns between a first end and a second end. The first end
of the secondary metal trace is connected to the second end of the
primary metal trace. The second end of the secondary metal trace is
configured to be capable of being connected to an output node. The
primary metal trace and the secondary metal trace are in respective
planes separated by a distance.
[0007] In some embodiments, the impedance matching device can
further include a first substrate configured to support the primary
metal trace. In some embodiments, the impedance matching device can
further include an insulator layer implemented between the primary
metal trace and the secondary metal trace. The insulator layer can
have a thickness selected to provide the separation distance. The
impedance matching device can further include a conductive feature
implemented through the insulator layer. The conductive feature can
be configured to provide the connection between the first end of
the secondary metal trace and the second end of the primary metal
trace.
[0008] In some embodiments, the impedance matching device can
further include a second substrate configured to support the
secondary metal trace. The second substrate with the secondary
metal trace can be in a flip-mounted configuration with the first
substrate to provide the separation distance between the primary
metal trace and the secondary metal trace. Each of the first
substrate and the second substrate can include a mounting surface
opposite from a surface on which respective metal trace is
implemented on. The mounting surface of the first substrate can
include a plurality of contact pads configured to allow mounting of
the impedance matching device to a packaging substrate. The
mounting surface of the second substrate can be configured to allow
mounting of a die thereon. The mounting surface of the second
substrate can be substantially flat.
[0009] In some embodiments, the impedance matching device can be an
integrated passive device (IPD). In some embodiments, the primary
metal trace can be wider than the secondary metal trace. In some
embodiments, the primary metal trace can be thicker than the
secondary metal trace. The primary metal trace can be configured to
provide passage of a DC current for the PA. The primary metal trace
can be further configured to provide a low impedance path for an RF
current. The secondary metal trace and its separation distance with
the primary metal trace can be configured to provide strong
coupling between the primary and secondary metal traces.
[0010] In some embodiments, the primary metal trace and the second
metal trace can be configured as an autotransformer. The impedance
matching device can further include one or more circuit elements
configured to provide matching functionality on either or both
sides of the autotransformer.
[0011] According to a number of implementations, the present
disclosure relates to a method for fabricating an impedance
matching device. The method includes forming a primary metal trace.
The primary metal trace has one or more turns between a first end
and a second end, with the first end of the primary metal trace
configured to be capable of being connected to a voltage source for
a power amplifier (PA), and the second end of the primary metal
trace configured to be capable of being connected to an output of
the PA. The method further includes implementing a secondary metal
trace relative to the primary metal trace. The secondary metal
trace has one or more turns between a first end and a second end,
with the first end of the secondary metal trace connected to the
second end of the primary metal trace, and the second end of the
secondary metal trace configured to be capable of being connected
to an output node. The primary metal trace and the secondary metal
trace are in respective planes separated by a distance.
[0012] In a number of teachings, the present disclosure relates to
a radio-frequency (RF) module that includes a packaging substrate
configured to receive a plurality of components. The RF module
further includes a power amplifier (PA) die implemented on the
packaging substrate. The PA die includes an output node configured
to provide an amplified RF signal. The RF module further includes
an impedance matching device implemented on the packaging
substrate. The impedance matching device includes a primary metal
trace having one or more turns between a first end and a second
end. The first end of the primary metal trace is connected to a
voltage source for the PA die, and the second end of the primary
metal trace is connected to the output node of the PA die. The
impedance matching device further includes a secondary metal trace
having one or more turns between a first end and a second end. The
first end of the secondary metal trace is connected to the second
end of the primary metal trace, and the second end of the secondary
metal trace is connected to an output node of the impedance
matching device. The primary metal trace and the secondary metal
trace are in respective planes separated by a distance.
[0013] In some embodiments, the impedance matching device can be
implemented as an integrated passive device (IPD). The IPD can
include a first side and a second side. The first side can be
configured to facilitate mounting of the IPD on the packaging
substrate, and the second side can be configured to allow mounting
of a component to thereby yield a stack configuration between the
IPD and the component. The first side can be configured to allow
flip-chip mounting of the IPD on the packaging substrate. The
second side can include a substantially flat surface suitable for
mounting of the component. The component can include a band
selection switch device. The stack configuration can allow a
reduction in lateral size of the RF module.
[0014] In some embodiments, the packaging substrate can include a
laminate substrate. The IPD having the first and second metal
traces can allow the laminate substrate to have a reduced number of
layers.
[0015] In some embodiments, the IPD can be positioned adjacent to
the PA die to reduce distances associated with connections between
the IPD and the PA die. In some embodiments, the RF module can be a
front-end module (FEM).
[0016] In accordance with an number of implementations, the present
disclosure relates to a wireless device that includes a transceiver
configured to generate a radio-frequency (RF) signal, and a power
amplifier (PA) configured to amplify the RF signal. The wireless
device further includes an impedance matching device configured to
impedance match the amplified RF signal. The impedance matching
device includes a primary metal trace having one or more turns
between a first end and a second end. The first end of the primary
metal trace is connected to a voltage source for the PA. The second
end of the primary metal trace is connected to an output node of
the PA. The impedance matching device further includes a secondary
metal trace having one or more turns between a first end and a
second end. The first end of the secondary metal trace is connected
to the second end of the primary metal trace. The second end of the
secondary metal trace is connected to an output node of the
impedance matching device. The primary metal trace and the
secondary metal trace are in respective planes separated by a
distance. The wireless device further includes an antenna in
communication with the output node of the impedance matching
device. The antenna is configured to facilitate transmission of the
amplified and matched RF signal.
[0017] In some implementations, the present disclosure relates to
an integrated passive device (IPD) that includes a body and an
autotransformer implemented within the body. The autotransformer
includes a primary metal trace having one or more turns between a
first end and a second end, with the first end of the primary metal
trace defining a first node, and the second end of the primary
metal trace defining a tap node. The autotransformer further
includes a secondary metal trace having one or more turns between a
first end and a second end, with the first end of the secondary
metal trace being connected to the tap node, and the second end of
the secondary metal trace defining a second node. The primary metal
trace and the secondary metal trace are in respective planes
separated by a distance. The IPD further includes a plurality of
contact features implemented to provide electrical connections
between the autotransformer and a first substrate.
[0018] In some embodiments, the first substrate can be configured
to support the primary metal trace. The body can include a second
substrate configured to support the second metal trace. The second
substrate can be in a flip-mounted configuration with respect to
the first substrate to provide the separation distance between the
primary metal trace and the secondary metal trace. The first
substrate can include a laminate substrate, and the second
substrate can include a die substrate.
[0019] In some embodiments, the body can include a surface defined
by a side of the second substrate opposite from a side on which the
secondary metal trace is implemented on. The surface can include a
substantially flat surface that allows mounting of one or more
components thereon.
[0020] In some embodiments, the IPD can further include an
insulator layer implemented between the primary metal trace and the
secondary metal trace. The insulator layer can have a thickness
selected to provide the separation distance. The IPD can further
include one or more conductive features implemented through the
insulator layer. The conductive feature can be configured to
provide one or more electrical connections between the primary
metal trace and the secondary metal trace. The insulator layer can
include a dielectric material such as benzocyclobutene (BCB),
polyimide, SiN (silicon nitride), or SiO2 (silicon dioxide).
[0021] In some embodiments, the primary metal trace can be wider
than the secondary metal trace. The primary metal trace can be
thicker than the secondary metal trace.
[0022] In some embodiments, the IPD can further include one or more
circuit elements configured to provide matching functionality on
either or both sides of the autotransformer. The IPD can be an
impedance matching device configured to match impedance for an
output of a power amplifier (PA). The primary metal trace can be
configured to provide passage of a DC current for the PA. The
primary metal trace can be further configured to provide a low
impedance path for an RF current. The secondary metal trace and its
separation distance with the primary metal trace can be configured
to provide strong coupling between the primary and secondary metal
traces.
[0023] In some teachings, the present disclosure relates to a
method for fabricating an integrated passive device (IPD). The
method includes providing or forming each of a first substrate and
a second substrate. The method further includes implementing a
primary metal trace on the first substrate, with the primary metal
trace having one or more turns between a first end and a second
end. The method further includes implementing a secondary metal
trace on the second substrate, with the secondary metal trace
having one or more turns between a first end and a second end. The
method further includes flip-mounting the second substrate on the
first substrate to provide a desired separation distance between
the primary metal trace and the secondary metal trace. The
flip-mounting includes formation of one or more electrical
connections between the primary metal trace and the secondary metal
trace to form an autotransformer.
[0024] In some embodiments, the method can further include forming
an insulator layer between the primary metal trace and the
secondary metal trace.
[0025] According to a number of implementations, the present
disclosure relates to a radio-frequency (RF) module that includes a
packaging substrate configured to receive a plurality of
components. The RF module further includes a power amplifier (PA)
die implemented on the packaging substrate. The PA die includes an
output node configured to provide an amplified radio-frequency (RF)
signal. The RF module further includes an integrated passive device
(IPD) implemented on the packaging substrate. The IPD is configured
to receive the amplified RF signal from the PA die. The IPD
includes a body, and an autotransformer implemented within the
body. The autotransformer is configured to facilitate impedance
matching of the amplified RF signal. The RF module further includes
a plurality of contact features implemented to provide electrical
connections between the autotransformer and the packaging
substrate.
[0026] In some embodiments, the packaging substrate can be
configured to support a primary metal trace of the autotransformer,
and the body can include a die substrate configured to support a
secondary metal trace of the autotransformer. The die substrate can
be in a flip-mounted configuration with respect to the packaging
substrate to provide the separation distance between the primary
metal trace and the secondary metal trace. The body can include a
surface defined by a side of the die substrate opposite from a side
on which the secondary metal trace is implemented on. The RF module
can further include a component mounted on the surface of the body
in a stacked configuration. Such a component can include a band
selection switch device. The stack configuration can allow a
reduction in lateral size of the RF module.
[0027] In some embodiments, the packaging substrate can include a
laminate substrate. The IPD having the autotransformer can allow
the laminate substrate to have a reduced number of layers.
[0028] In some embodiments, the IPD can be positioned adjacent to
the PA die to reduce distances associated with connections between
the IPD and the PA die. In some embodiments, the RF module can be a
front-end module (FEM).
[0029] In a number of implementations, the present disclosure
relates to a wireless device having a transceiver configured to
generate a radio-frequency (RF) signal, and a power amplifier (PA)
configured to amplify the RF signal. The wireless device further
includes an impedance matching device implemented as an integrated
passive device (IPD). The IPD is configured to receive the
amplified RF signal from the PA. The IPD includes a body and an
autotransformer implemented within the body. The autotransformer is
configured to facilitate impedance matching of the amplified RF
signal. The wireless device further includes an antenna in
communication with the IPD. The antenna is configured to facilitate
transmission of the amplified and matched RF signal.
[0030] For purposes of summarizing the disclosure, certain aspects,
advantages and novel features of the inventions have been described
herein. It is to be understood that not necessarily all such
advantages may be achieved in accordance with any particular
embodiment of the invention. Thus, the invention may be embodied or
carried out in a manner that achieves or optimizes one advantage or
group of advantages as taught herein without necessarily achieving
other advantages as may be taught or suggested herein.
[0031] The present disclosure relates to U.S. patent application
No. ______ [Attorney Docket 75900-50065US], titled
"AUTOTRANSFORMER-BASED IMPEDANCE MATCHING CIRCUITS AND METHODS FOR
RADIO-FREQUENCY APPLICATIONS," filed on even date herewith and
hereby incorporated by reference herein in its entirety.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] FIG. 1 shows that in some embodiments, a matching circuit
having one or more features of the present disclosure can be based
on an autotransformer.
[0033] FIG. 2A shows that in some embodiments, a matching circuit
having one or more features described herein can be implemented as
an integrated passive device (IPD).
[0034] FIG. 2B shows that in some embodiments, a matching circuit
having one or more features described herein can be implemented
partly in an IPD and partly in a substrate.
[0035] FIG. 3 shows that in some embodiments, a matching circuit
having one or more features described herein can be implemented to
match an output of a power amplifier (PA).
[0036] FIG. 4 shows an example configuration of a conventional
impedance matching circuit coupled to an output of a PA.
[0037] FIG. 5 shows an example configuration of an impedance
matching circuit coupled to an output of a PA.
[0038] FIG. 6 shows another example configuration of an impedance
matching circuit coupled to an output of a PA.
[0039] FIGS. 7 and 8 show examples of impedance property of an
autotransformer by itself.
[0040] FIGS. 9 and 10 show examples of impedance property of an
autotransformer with matching on the output side.
[0041] FIGS. 11-13 show examples of impedance property of an
autotransformer with matching on the input side.
[0042] FIG. 14 shows an example of a matching circuit having
matching on the input side and the output side of an
autotransformer.
[0043] FIG. 15 shows an example configuration where the matching
circuit of FIG. 14 includes some of the inductances being provided
by conductors such as wirebonds.
[0044] FIG. 16 shows an example configuration where an
autotransformer having tightly coupled primary and secondary coils
is implemented as an IPD.
[0045] FIGS. 17A-17D show various stages of an example fabrication
process for the example IPD of FIG. 16.
[0046] FIG. 18 shows a process that can be implemented to fabricate
the example IPD of FIGS. 16 and 17.
[0047] FIG. 19 shows another example configuration where an
autotransformer having tightly coupled primary and secondary coils
is implemented such that the primary coil is on a first substrate
and the secondary coil is on a second substrate.
[0048] FIGS. 20A-20D show various stages of an example fabrication
process for the example IPD of FIG. 19.
[0049] FIG. 21 shows a process that can be implemented to fabricate
the example IPD of FIGS. 19 and 20.
[0050] FIG. 22 shows examples of various design parameters
associated with the example IPD of FIGS. 19-21.
[0051] FIGS. 23A and 23B show examples of coupling coefficient K as
a function of insulator thickness at two example frequencies for
various primary coil thickness values.
[0052] FIG. 24 shows examples of insertion loss as a function of
insulator thickness for various primary coil thickness values.
[0053] FIG. 25 shows an example of how overall coil size can be
designed.
[0054] FIG. 26 shows an example of how trace width of a coil can be
designed.
[0055] FIG. 27 shows another example of how trace width of a coil
can be designed.
[0056] FIG. 28 shows that in some embodiments, an
autotransformer-based matching circuit implemented as an IPD can be
configured to provide a surface for mounting one or more components
thereon.
[0057] FIG. 29 shows another example of an autotransformer-based
matching circuit implemented as an IPD so as to provide a surface
for mounting one or more components thereon.
[0058] FIG. 30 shows an example IPD having one autotransformer
configured in a manner similar to the example of FIG. 28.
[0059] FIG. 31 shows an example IPD having one autotransformer
configured in a manner similar to the example of FIG. 29.
[0060] FIG. 32 shows that in some embodiments, an IPD can include
more than one autotransformer.
[0061] FIG. 33 shows an example configuration where another
component is mounted on the surface of an IPD similar to the
examples of FIGS. 28-32.
[0062] FIGS. 34A and 34B show side and plan views of connections
that can be implemented for the stacked configuration of FIG.
33.
[0063] FIGS. 35A and 35B show side and plan views of an example
configuration where two components are mounted on the surface of an
IPD similar to the examples of FIGS. 28-32.
[0064] FIG. 36 shows an example of how the size of a module having
one or more features as described herein can be reduced.
[0065] FIGS. 37 and 38 show examples of how a module having one or
more features as described herein can allow use of a laminate
substrate having a reduced number of laminate layers.
[0066] FIG. 39 shows an example of a module that can benefit from
one or more features as described herein.
[0067] FIG. 40 shows an example of a wireless device that can
benefit from one or more features as described herein.
DETAILED DESCRIPTION OF SOME EMBODIMENTS
[0068] The headings provided herein, if any, are for convenience
only and do not necessarily affect the scope or meaning of the
claimed invention.
[0069] Described herein are examples of autotransformers that can
be utilized in, for example, impedance matching circuits for
radio-frequency (RF) applications. In some implementations, use of
an autotransformer in an impedance matching circuit can result in
significant reduction in size of the matching circuit. Accordingly,
an area of an RF module such as a multi band multi mode front end
MCM (multi-chip module) can also be reduced significantly.
[0070] In some implementations, additional benefits can be realized
by use of an autotransformer in an impedance matching circuit. For
example, a need for a DC choke in a matching circuit can be
eliminated. In another example, a matching circuit having an
autotransformer can have a wider usable bandwidth than that of a
conventional matching circuit. Although various examples are
described herein in the context of autotransformers, it will be
understood that one or more features of the present disclosure can
also be implemented in other types of transformer configurations,
including those where first and second coils are not electrically
connected.
[0071] FIG. 1 shows that in some embodiments, one or more features
of the present disclosure can be implemented as an autotransformer
140, and such an autotransformer can be implemented in a matching
circuit 100. Although described in the example context of such a
matching circuit, it will be understood that one or more features
of the present disclosure can be implemented in other RF
circuits.
[0072] FIG. 2A shows that in some embodiments, a matching circuit
100 or a portion of such a matching circuit having one or more
features described herein can be implemented in an integrated
passive device (IPD) 102. Examples of such an implementation are
described herein in greater detail
[0073] FIG. 2B shows that in some embodiments, a matching circuit
100 or a portion of such a matching circuit having one or more
features described herein can be implemented in an IPD 102 and a
substrate 104 (e.g., a laminate packaging substrate). Examples of
such an implementation are described herein in greater detail.
[0074] FIG. 3 shows that in some embodiments, a matching circuit
100 having one or more features described herein can be implemented
to provide impedance matching for an output 110 of a power
amplifier (PA) 108. Although described in such an example context,
it will be understood that the matching circuit 100 can also be
implemented in other applications.
[0075] FIG. 4 shows an example configuration 120 of a conventional
impedance matching circuit coupled to an output of an amplifying
transistor 122. An RF signal is shown to be input into the base of
the transistor 122, and an amplified RF signal is shown to be
output through the collector of the transistor 122. As shown, the
amplified RF signal can be subjected to one or more harmonic traps,
as well as a DC block, before reaching an output node (RFOUT).
[0076] In the example configuration 120, an impedance matching
circuit is shown to include a choke inductance 124. The choke
inductance 124 is shown to be implemented between a collector
voltage (Vdc) node and the collector of the transistor 122. The
collector voltage node is also shown to be coupled to ground
through a decoupling capacitance 126.
[0077] In the example configuration 120, the collector of the
amplifying transistor 122 is shown to be coupled to the output node
(RFOUT) through an inductance L1 and a DC block capacitance
(DC_Block). Capacitive couplings with ground before (through
capacitance C1) and after (through capacitance C2) the inductance
L1 can be configured to provide, for example, low pass filtering
functionality for the amplified RF signal. Although the example
shunts to ground involving C1 and C2 are described in the context
of capacitive shunts, it will be understood that any combination of
capacitance, inductance and resistance elements can also be
utilized. Such shunt paths having capacitance, inductance,
resistance, or any combination thereof can also be implemented in
other shunt examples described herein.
[0078] FIG. 5 shows an example configuration 130 of an impedance
matching circuit coupled to an output of an amplifying transistor
122. Similar to the example of FIG. 4, an RF signal is shown to be
input into the base of the transistor 122, and an amplified RF
signal is shown to be output through the collector of the
transistor 122.
[0079] The impedance matching circuit of FIG. 5 is shown to include
an autotransformer 140 having a primary coil 144 and a secondary
coil 148 connected in series. The primary end (node 142) of the
autotransformer 140 is shown to be connected to a collector voltage
(Vdc) node. The secondary end (node 150) of the autotransformer 140
is shown to be connected to a capacitance C2 which is in turn
connected to an output node (RFOUT). In some embodiments, C2 can be
configured to resonate out leakage inductance of the
autotransformer 140. In such embodiments, C2 can be approximated as
C2=1/[(2.pi.f).sup.2L.sub.leak].
[0080] In FIG. 5, a capacitance C1 is shown to be connected between
the Vdc node and tap a node 146 that is between the primary coil
144 and the secondary coil 148. In some embodiments, C1 can be
configured to resonate out magnetizing inductance of the
autotransformer 140. In such embodiments, C1 can be approximated as
C1=1/[(2.pi.f).sup.2L.sub.mag].
[0081] In FIG. 5, the collector output of the transistor 122 is
shown to be connected to the tap node 146 between the primary and
secondary coils 144, 148. Also, a decoupling capacitance 143 is
shown to terminate an RF current at the Vdc node (142).
[0082] Configured in the foregoing manner, the primary coil 144 can
be used to pass a DC current (Vdc) of the transistor 122 as well as
the RF current of the low impedance circuit. Thus, the primary coil
144 can be re-used in both low impedance and high impedance
branches of the circuit, thereby reducing the size and electrical
loss of the matching circuit.
[0083] FIG. 6 shows another example configuration 132 of an
impedance matching circuit coupled to an output of an amplifying
transistor 122. Similar to the example of FIG. 4, an RF signal is
shown to be input into the base of the transistor 122, and an
amplified RF signal is shown to be output through the collector of
the transistor 122.
[0084] The impedance matching circuit of FIG. 6 is shown to include
an autotransformer 140 having a primary coil 144 and a secondary
coil 148 connected in series. The primary end (node 142) of the
autotransformer 140 is shown to be connected to a Vdc node. The
secondary end (node 150) of the autotransformer 140 is shown to be
connected to a capacitance C2 which is in turn connected to an
output node (RFOUT). In some embodiments, C2 can be configured to
resonate out leakage inductance of the autotransformer 140. In such
embodiments, C2 can be approximated as
C2=1/[(2.pi.f).sup.2L.sub.leak].
[0085] In FIG. 6, the collector output of the transistor 122 is
shown to be connected to a tap node 146 between the primary and
secondary coils 144, 148. Also, a decoupling capacitor is shown to
terminate an RF current at the Vdc node (142).
[0086] FIG. 6 shows that one or more harmonic traps can be
implemented to achieve harmonic termination conditions for various
classes of operation. For example, a primary matching capacitance
C1 and an inductance (Trap.sub.--2fo) are shown to be arranged in
series between the tap node 146 and ground; and such an arrangement
can be utilize as a second harmonic trap. In another example, a
secondary matching capacitance (C.sub.--3fo) can be implemented
between the tap node 146 and the secondary end node 150 to block
third harmonic.
[0087] FIGS. 7-15 show various non-limiting examples of design
features that can be considered and implemented to yield desirable
performance of matching circuits based on autotransformers. FIGS. 7
and 8 show examples of impedance property of an autotransformer by
itself. More particularly, FIG. 7 shows an autotransformer 140
having a primary inductance L1 and a secondary inductance L2. The
autotransformer 140 is shown to be provided with an input (In) at a
tap node between L1 and L2. An output (Out) is shown to be at an
end node of L2. Accordingly, input and output reflection
coefficients S11, S22 can be characterized as shown.
[0088] FIG. 8 shows a Smith plot of impedance associated with S11
(S(1,1)) and S22 (S(2,2)) of the example of FIG. 7, as frequency is
swept from 50 MHz to 10 GHz. For the Smith plot of FIG. 8, L1=1 nH,
L2=16 nH, and a turn ratio of 4 (e.g., N1=1, N2=4), resulting in a
coupling coefficient Kc of approximately 0.9. It is noted that with
such a configuration, higher coil loss can occur in the form of,
resulting from and/or resulting in, for example, higher Re(Zin) and
more Z-ratio dispersion. It is also noted that lower primary
inductance can occur in the form of, resulting from and/or
resulting in, for example, smaller bandwidth and higher residual
inductance. It is also noted that lower coupling efficiency can
occur in the form of, resulting from and/or resulting in, for
example, lower bandwidth and higher residual inductance.
[0089] FIGS. 9 and 10 show examples of impedance property with
matching of the output side of an autotransformer. More
particularly, FIG. 9 shows an autotransformer 140 having a primary
inductance L1 and a secondary inductance L2. The autotransformer
140 is shown to be provided with an input (In) at a tap node
between L1 and L2. An output (Out) is shown to be obtained from an
end node 160 of L2 through a DC block capacitance (C_block). A
shunt arm with a capacitance (C_shunt) and an inductance 162 is
shown to couple the node 160 with ground. Accordingly, input and
output reflection coefficients S11, S22 of the autotransformer 140
can be characterized as shown.
[0090] FIG. 10 shows a Smith plot of impedance associated with S11
(S(1,1)) and S22 (S(2,2)) of the example of FIG. 9, as frequency is
swept from 0 Hz (DC) to 6 GHz. For the Smith plot of FIG. 10, the
turn ratio between the secondary coil (N2) and the primary coil
(N1) is 3.75 (e.g., N1=1, N2=3.75). It is noted that the shunt arm
(with C_shunt) and the DC block capacitance (C_block) can be
configured to move the impedances associated with both S11 and S22
toward a matched impedance Zo. For example, the shunt arm (with
C_shunt) can be configured to move the impedances from impedance
values m1 and m2 towards Zo along, for example, an impedance
profile 164. In another example, the DC block capacitance (C_block)
can be configured to further move the impedances resulting from the
shunt arm (with C_shunt) toward Zo along, for example an impedance
profile 166.
[0091] FIGS. 11-13 show examples of impedance property with
matching of the input side of an autotransformer. More
particularly, FIG. 11 shows an autotransformer 140 having a primary
inductance L1 and a secondary inductance L2. The autotransformer
140 is shown to be provided with an input (In) through an
inductance (L_series) to a tap node 170 between L1 and L2. An
output (Out) is shown to be at an end node of L2. A shunt arm with
a capacitance (C_shunt) and an inductance 172 is shown to couple
the node 170 with ground. A capacitance C1 is shown to provide a
parallel path with the primary inductance L1, between the node 170
and an end node 174 of L1. The end node 174 is shown to be coupled
to ground through a decoupling capacitance (C_decouple). In some
embodiments, either or both of the shunt capacitance (C_shunt) and
the parallel-path capacitance (C1) can be implemented. Accordingly,
input and output reflection coefficients S11, S22 of the
autotransformer 140 can be characterized as shown.
[0092] In some embodiments, inductance for one or more of the
inductances of the example of FIG. 11 can be provided by one or
more conductor features between two nodes. For example, and as
shown in FIG. 12, the inductance L_series can be provided by an
assembly of one or more wirebonds 180 between conductive pads 176,
178. The conductive pad 176 can be connected to the input node
(In), and the conductive pad 178 can be connected to the node 170.
As described herein, such wirebonds can be configured to provide
desired impedance values for various matching features implemented
with autotransformers.
[0093] FIG. 13 shows a Smith plot of impedance associated with S11
(S(1,1)) and S22 (S(2,2)) of the example of FIG. 11, as frequency
is swept from 0 Hz (DC) to 6 GHz. For the Smith plot of FIG. 13,
the turn ratio between the secondary coil (N2) and the primary coil
(N1) is 3.75 (e.g., N1=1, N2=3.75). Similar results can be obtained
for configurations each having one of the shunt capacitance
(C_shunt) and the parallel-path capacitance (C1), but not the
other. It is noted that either of the shunt arm (with C_shunt) and
the parallel-path capacitance (C1), and the inductance (L_series),
can be configured to move the impedances associated with both S11
and S22 toward a matched impedance Zo. For example, the shunt arm
(with C_shunt) can be configured to move the impedances from
impedance values m1 and m2 along, for example, an impedance profile
182. In another example, the inductance (L_series) can be
configured to further move the impedances resulting from the shunt
arm (with C_shunt) toward Zo along, for example an impedance
profile 184.
[0094] FIG. 14 shows an example of a matching circuit with matching
on both of the input side and the output side of an
autotransformer. Such a matching circuit can include one or more
features described in the examples of FIGS. 9-13, as well as one or
more features that can facilitate combining of input-side matching
and output-side matching.
[0095] In the example of FIG. 14, an autotransformer 140 having a
primary inductance L1 and a secondary inductance L2 is shown to be
provided with an input (In) through an inductance (L_series) to a
tap node 190 between L1 and L2. An output (Out) is shown to be
obtained from an end node of L2, through a capacitance C2, and an
inductance L4. On the input side, a shunt arm with a capacitance C3
and an inductance L7 is shown to couple the node 190 with ground.
Also on the input side, a shunt arm with a capacitance C5 and an
inductance L8 is shown to couple the input node with ground. On the
output side, a shunt arm with a capacitance C1 and an inductance L3
is shown to couple a node 192 between C2 and L4 with ground.
[0096] In the example of FIG. 14, an end node 194 of the primary
inductance L1 can be a supply voltage (VCC) node. Decoupling
functionality can be provided by an inductance L5 between the VCC
node 194 and a decoupling capacitance (C_decouple) which is in turn
connected to ground. A coupling path between the VCC node and
ground through a capacitance C4 and an inductance L6 can be
configured to provide VCC bypass and primary RF ground
functionality.
[0097] In the example of FIG. 14, the input-side shunt arm with C3
and L7 can be configured to provide primary residual tuning
functionality, as well as a trap for second harmonic. The
output-side shunt arm with C1 and L3 can be configured to provide
output (S22) match tuning functionality, as well as a trap for
third harmonic. The capacitance C2 can be configured to provide DC
blocking and output matching functionalities.
[0098] In the example of FIG. 14, the shunt arm with C5 and L8 can
be configured to trap second harmonic. In some embodiments, such a
shunt arm can be implemented in a die that is separate from a
device (e.g., an IPD) having the autotransformer 140 and related
matching features. Examples related to such a device are described
herein in greater detail.
[0099] FIG. 15 shows the same matching configuration as in the
example of FIG. 14, but with selected inductances provided by
conductor features such as wirebonds. Such wirebonds can be
implemented to provide electrical connections between a matching
circuit device 100 (e.g., an IPD) and other components or nodes
outside of the device 100. For example, the inductance L_series can
be implemented as one or more wirebonds to connect the node 190 to
an output of a PA (not shown). The second-harmonic trap with C5 and
L8, shown to be outside of the device 100, can be implemented on
the same die as the PA.
[0100] In other examples, inductances associated with L5, L6, L7,
L4 and L4 can be provided by respective assemblies, with each
assembly having one or more wirebonds configured to provide
electrical connection between the device 100 and a node outside of
the device 100. For example, the wirebond-assemblies associated
with L7, L3 and L6 can provide connections to grounding pads
outside of the device. The wirebond-assembly associated with L4 can
provide connection of the node 192 to an RF output pad outside of
the device 100.
[0101] In some embodiments, some or all of matching circuits
described herein (e.g., including the examples shown in FIGS. 5-15)
can be implemented as an integrated passive device (IPD). FIG. 16
shows an example configuration where an autotransformer 140 having
tightly coupled primary and secondary coils 144, 148 is implemented
as an IPD 200. Although not shown, other components (e.g.,
capacitances, inductances, conductive paths, etc.) can be included
in the IPD 200.
[0102] More particularly, the IPD 200 is shown to include a die
substrate 202 which can be, for example, an insulating or
high-resistivity semiconductor substrate. The primary coil 144 can
be implemented as one or more turns of a metal trace 204 formed on
a surface of the die substrate 202. The primary metal trace 204 can
be configured to allow handling of DC current of the amplifying
transistor (e.g., 122 in FIGS. 5 and 6) as well as RF current of
the low impedance circuit.
[0103] The secondary coil 148 can be implemented as one or more
turns of a metal trace 206 formed over the primary metal trace 204.
In the example shown, the secondary metal trace 206 has multiple
turns, and the primary metal trace 204 has one turn. It will be
understood that other numbers of turns for each of the primary and
secondary metal traces are also possible. It will also be
understood that each of the primary and secondary metal traces can
have non-integer number of turns, including less than one turn.
[0104] An electrically insulating layer can be provided between the
primary metal trace 204 and the secondary metal trace 206.
Thickness of such an insulating layer can provide a separation
distance between the primary and secondary metal traces 204, 206.
Accordingly, such a thickness of the insulating layer can be
selected to provide sufficient separation, yet close enough for
strong coupling between the two coils 144, 148.
[0105] As shown in FIG. 16, one end of the primary metal trace 204
can be electrically connected to one end of the secondary metal
trace 206. For example, suppose that a contact pad 142 (of the
primary metal trace 204) is to be electrically connected to a Vdc
node, and a contact pad 146 (also of the primary metal trace 204)
is to be electrically connected to a collector (thereby act as an
input of the autotransformer). Further, suppose that a contact pad
150 (of the secondary metal trace 206) is to be connected to an RF
output (and also act as an output of the autotransformer). Then, an
inner end 210 of the secondary metal trace 206 can be electrically
connected to the contact pad 146 by, for example, an inter-layer
conductive via 208.
[0106] As indicated in FIG. 16, a sectional view of a portion of
the IPD 200 is shown in FIG. 17. More particularly, FIGS. 17A-17D
show various stages of an example IPD fabrication process. FIG. 17A
shows a stage where a die substrate 202 can be provided, and a
primary metal trace 204 can be formed on an upper surface of the
die substrate 202. In some embodiments, the primary metal trace 204
can be formed by utilizing techniques such as masking, metal
deposition, and etching.
[0107] FIG. 17B shows a stage where an electrically insulating
layer 212 can be formed so as to cover the primary metal trace 204.
In some embodiments, materials such as oxide or dielectric material
can be deposited so as to form the insulating layer 212.
[0108] FIG. 17C shows a stage where an opening 214 can be formed
through the insulating layer. In some embodiments, such an opening
can be formed by patterned etching, focused laser, etc.
[0109] FIG. 17D shows a stage where a secondary metal trace 208 can
be formed on the insulating layer 212. In some embodiments, the
secondary metal trace 208 can be formed by utilizing techniques
such as printing, masking, metal deposition, and etching. Such a
formation of the secondary metal trace 208 can result in the
opening 214 (FIG. 17C) being filled so as to yield a conductive
inter-layer via 208.
[0110] As further shown in FIG. 17D, the thickness (d1) of the
insulating layer 212 between the primary and secondary metal traces
204, 206 can be selected to provide sufficient separation of the
metal traces, yet provide a desirable coupling between the two
metal traces.
[0111] FIG. 18 shows a process 220 that can be implemented to
fabricate an IPD such as the example described in reference to
FIGS. 16 and 17. In block 222, a substrate can be provided or
formed. In block 224, a first coil can be formed on the substrate.
In block 226, an insulator layer can be formed over the first coil.
In block 228, a conductive feature can be formed through the
insulator layer to form an electrical connection with one end of
the first coil. Such a conductive feature can be formed separately,
or during the formation of a second coil. In block 230, a second
coil can be formed over the insulator layer such that one end of
the second coil is electrically connected with the conductive
feature to thereby form an autotransformer circuit. The conductive
feature which connects the ends of the first and second coils can
provide a tap node for the autotransformer circuit. The first coil
can be configured as a primary coil, and the second coil can be
configured as a secondary coil.
[0112] In some embodiments, the tap node can be electrically
connected with, or be configured to accept an electrical connection
with, an output of a power amplifier (PA) in block 232. In block
234, the other end of the second coil can be electrically connected
with, or be configured to accept an electrical connection with, an
output of a matching circuit that includes the autotransformer.
[0113] As described herein, such a matching circuit can include one
or more components or circuits for providing matching on either or
both sides of the autotransformer. In block 236, such components or
circuits that are part of the IPD can be formed or provided to
yield a desired impedance matching functionality for the IPD.
[0114] In some embodiments, some or all of matching circuits such
as the examples shown in FIGS. 5-15 can be implemented partly as an
IPD, and partly on a packaging substrate of a module 300 on which
the IPD is mounted to. FIG. 19 shows an example configuration where
an autotransformer 140 having primary and secondary coils 144, 148
is implemented so that the primary coil 144 is implemented on a
packaging substrate 302, and the secondary coil 148 is implemented
on a die substrate 312. Although not shown, other components can
also be provided.
[0115] In the example of FIG. 19, the primary coil 144 can also be
implemented on a die substrate 302 such that the module 300
includes first and second die (302, 312) with their respective
coils (144, 148). Similarly, both of the primary and secondary
coils 144, 148 can also be implemented on respective packaging
substrates. Accordingly, a substrate on which a coil is implemented
on can be a die substrate such as a semiconductor substrate, a
packaging substrate such as a laminate substrate, or any
combination thereof. Thus, the module 300 can be an IPD itself, and
is described as such in some of the examples disclosed herein.
[0116] In the example of FIG. 19, the module 300 is shown to
include the second substrate 312 mounted on the first substrate
302. The second substrate 312 can be, for example, an insulating or
high-resistivity semiconductor substrate, or a laminate substrate.
The first substrate 302 can be, for example, a laminate substrate,
or an insulating or high-resistivity semiconductor substrate.
[0117] The primary coil 144 can be implemented as one or more turns
of a metal trace 304 formed on a surface of the substrate 302. The
primary metal trace 304 can be configured to allow handling of DC
current of the amplifying transistor (e.g., 122 in FIGS. 5 and 6)
as well as RF current of the low impedance circuit.
[0118] The secondary coil 148 can be implemented as one or more
turns of a metal trace 314 formed on a surface of the substrate
312. In the example shown, the secondary metal trace 314 has
multiple turns, and the primary metal trace 304 has one turn. It
will be understood that other numbers of turns for each of the
primary and secondary metal traces are also possible.
[0119] In the example shown in FIG. 19, the side of the substrate
312 on which the secondary metal trace 314 is formed is shown to be
mounted on the side of the substrate 302 on which the primary metal
trace 304 is formed. In some embodiments, such a mounting
configuration can be facilitated by, for example, surface mount
technology (SMT). For example, bumpless connections (e.g., about 25
.mu.m stand off distance) can be utilized to mount the secondary
metal trace 314 on the primary metal trace 304 at one or more
locations. For example, a bumpless connection 308 is shown to
electrically connect an inner end 310 of the secondary metal trace
314 with a contact pad 146. In another example, a bumpless
connection 322 is shown to electrically connect a contact pad 150
on an outer end of the secondary metal trace 314 with a contact pad
320 on the substrate 302.
[0120] In the example of FIG. 19, the contact pads 142, 146 and 320
(with 150) on the packaging substrate 302 can form the nodes as
described in reference to FIGS. 5-15. As described herein, the
contact pads 142, 146 and 320 can be electrically connected to
locations on the lower surface of the substrate 302.
[0121] In some implementations, an electrically insulating material
can be introduced between the primary and secondary metal traces
304, 306. For example, the space between the mounted secondary
metal trace 306 and the primary metal trace 304 can be under-filled
with an insulating material such as a dielectric material. Such a
material can also fill the spaces between the traces of a given
coil. In FIG. 19, the insulating material between the primary and
secondary metal traces 304, 306 is indicated as a layer 330.
[0122] As indicated in FIG. 19, a sectional view of a portion of
the module/IPD 300 is shown in FIG. 20. More particularly, FIGS.
20A-20D show various stages of an example fabrication process. FIG.
20A shows a stage where a first substrate 302 can be provided, and
a primary metal trace 304 can be formed on an upper surface of the
first substrate 302. In some embodiments, the primary metal trace
304 can be formed by utilizing techniques such as masking, metal
deposition, and etching.
[0123] FIG. 20B shows a stage where a bumpless contact feature 308
can be formed on the primary metal trace 304. In some embodiments,
such a bumpless contact feature can be implemented using known SMT
techniques.
[0124] FIG. 20C shows a stage where an assembly of a secondary
metal trace 306 formed on a surface of a second substrate 312 can
be mounted on the primary metal trace 304. In the example shown,
the bumpless contact feature 308 can facilitate such a
mounting.
[0125] FIG. 20D shows a stage where an insulating material 330 can
be introduced between the primary metal trace 304 and the secondary
metal trace 306. Such material can be introduced by, for example,
under-filling the space between the primary and secondary metal
traces 304, 306. In some embodiments, the insulating material 330
can be, for example, a dielectric material.
[0126] As further shown in FIG. 20D, the distance (d2) between the
primary and secondary metal traces 304, 306 can be effectuated by,
for example, the dimension of the bumpless contact feature 308.
Such a distance can be selected to provide a number of features
such as a desirable coupling between the two coils, and a desirable
capacitance between the two coils.
[0127] In some embodiments, either or both of the primary and
second metal traces 304, 306 can be configured to provide a number
of desirable features. For example, thickness of a given metal
trace can be selected to provide a desired insertion loss to
thereby improve the autotransformer performance. In another
example, other parameters such as trace width and overall coil size
can be adjusted to yield desirable performance of the
autotransformer. Examples of design considerations based on such
parameters are described herein in greater detail.
[0128] In some embodiments, it may not be possible or practical to
position the primary and secondary metal traces 304, 306 of FIG.
20D as closely as in the example of FIG. 17D. Accordingly, coupling
efficiency may be reduced in such a situation. However, such an
effect can be compensated by one or more tuning capacitances
connected to the autotransformer.
[0129] FIG. 21 shows a process 340 that can be implemented to
fabricate the IPD described in reference to FIGS. 19 and 20. In
block 342, a first substrate can be provided or formed. In block
344, a first coil can be formed on the first substrate. In some
embodiments, such a coil can be a conductive trace patterned on a
surface of the substrate to form a spiral shaped coil. In block
346, a conductive feature can be formed on one end of the first
coil.
[0130] In block 348, a second substrate can be provided or formed.
In some embodiments, the second substrate may or may not be the
same type as the first substrate. In block 350, a second coil can
be formed on the second substrate. In some embodiments, such a coil
can be a conductive trace patterned on a surface of the substrate
to form a spiral shaped coil.
[0131] In block 352, the second substrate with the second coil
thereon can be flip mounted on the first substrate such that one
end of the second coil is connected with the conductive feature.
Such a connection between the first and second coils can form an
autotransformer with a tap at the conductive feature. In block 354,
an insulator layer can be formed between the first coil and the
second coil.
[0132] In some embodiments, the tap node can be electrically
connected with, or be configured to accept an electrical connection
with, an output of a power amplifier (PA). The other end of the
second coil can be electrically connected with, or be configured to
accept an electrical connection with, an output of a matching
circuit that includes the autotransformer. In the various examples
described in reference to FIGS. 16-21, conductive features can be
implemented to provide and/or facilitate electrical connection(s)
among the coils, as well as for input/output purpose. As described
herein, one or more features of the present disclosure can also be
implemented with other types of transformer configurations,
including those where the coils are not electrically connected with
each other. For such configurations, as well as other
configurations involving other electrical connection
configurations, conductive features can be implemented
appropriately to facilitate electrical connections, including those
for input/output purpose.
[0133] As described herein, such a matching circuit can include one
or more components or circuits for providing matching on either or
both sides of the autotransformer. Such components or circuits that
are part of the IPD can be formed or provided to yield a desired
impedance matching functionality for the IPD.
[0134] An IPD described in reference to FIGS. 19-21 can yield an
assembly of first and second coils 304, 314 in the form of traces
depicted in a cross-sectional view of FIG. 22. The first coil 304
is depicted as a trace having sectional dimensions of w1 (width)
and t1 (thickness). The second coil 314 is depicted as a trace
having sectional dimensions of w2 (width) and t2 (thickness). The
first and second coils 304, 314 are shown to be separated by a
distance of d2, and such a gap is shown to be filled by an
insulator material layer 330.
[0135] FIGS. 23-27 show examples of how some or all of the
foregoing parameters can be considered to yield desirable
properties of the autotransformers. For the examples described in
reference to FIGS. 23-27, the insulator layer 330 is formed from
dielectric material such as benzocyclobutene (BCB). Other
dielectric materials such as polyimide, SiN (silicon nitride), SiO2
(silicon dioxide), etc. can also be utilized as the insulator layer
330. Further, it will be understood that other materials (e.g.,
polymer compounds) can also be used.
[0136] FIGS. 23A and 23B show an example of how metal thickness of
a trace can be considered as a design factor. FIG. 23A shows plots
of coupling coefficient (K) as a function of insulator (BCB)
thickness (d2 in FIG. 22) for various thicknesses (t1=6, 10, 14, 20
.mu.m) of the primary trace (304), at a frequency of 850 MHz, and
with the primary and secondary trace widths (w1, w2) at 150 m.mu.
and 40 .mu.m, respectively. FIG. 23B shows the same plots, but at a
frequency of 1,950 MHz.
[0137] In the example of FIGS. 23A and 23B, it is noted that the
coupling coefficient K decreases monotonically with an increase in
BCB thickness, as generally expected. Among the different values of
the primary trace thickness (t1), the thinner primary traces appear
to have slightly higher coupling effects than the thicker ones.
[0138] FIG. 24 shows plots of insertion loss as a function of
insulator (BCB) thickness (d2 in FIG. 22) for various primary trace
thicknesses (t1=6, 10, 14, 20 .mu.m), for a primary trace width w1
of 150 .mu.m and a secondary trace width w2 of 50 .mu.m), at a
frequency of 1,950 MHz. It is noted that thicker primary traces in
general yield lower magnitude of loss.
[0139] FIG. 25 shows plots of insertion loss as a function of
primary trace width (w1 in FIG. 22) for various overall coil sizes
(800, 1000, 1200 .mu.m) with a fixed secondary trace width (w2=45
.mu.m), at a frequency of 1,950 MHz. For these plots, the following
parameters are fixed as follows: turn ratio of (N2:N1=3.75:1), t1=6
.mu.m, t2=6 .mu.m, and d2 (BCB)=6 .mu.m. Such examples can be
utilized to facilitate selection of design parameters such as
overall coil size.
[0140] FIG. 26 shows plots of insertion loss as a function of
primary trace width (w1 in FIG. 22) for various secondary trace
widths (30, 40, 50 .mu.m), at a frequency of 1,950 MHz. For these
plots, the following parameters are fixed as follows: overall coil
size=800 .mu.m, turn ratio of (N2:N1=3.75:1), t1=6 .mu.m, t2=6
.mu.m, and d2 (BCB)=6 .mu.m. It is noted that wider second trace
widths generally have lower loss magnitude. However, when the
primary trace width is small, such wider second trace widths seem
to yield higher loss magnitudes. It is also noted that for a given
second trace width, there is typically a minimum loss magnitude in
the primary trace width.
[0141] FIG. 27 shows plots of insertion loss as a function of
primary trace width (w1 in FIG. 22) for various secondary trace
widths (23, 30, 38 .mu.m), at a frequency of 1,950 MHz. For these
plots, the following parameters are fixed as follows: overall coil
size=600 .mu.m, turn ratio of (N2:N1=3.75:1), t1=6 .mu.m, t2=6
.mu.m, and d2 (BCB)=6 .mu.m. Similar to the 800 .mu.m coil size
example of FIG. 26, it is noted that wider second trace widths
generally have lower loss magnitude. However, when the primary
trace width is small, such wider second trace widths seem to yield
higher loss magnitudes. It is also noted that for a given second
trace width, there is typically a minimum loss magnitude in the
primary trace width.
[0142] FIGS. 28-40 show various examples of how IPDs as described
herein can provide advantageous features at different levels of
applications.
[0143] FIG. 28 shows an IPD 400 that is similar to the example
described in reference to FIGS. 19 and 20. The IPD 400 is shown to
include an autotransformer 140 having primary and secondary coils
(e.g., traces) 304, 314 that are spaced apart by, for example, an
insulator layer such as a BCB layer. Such an autotransformer can
have its end nodes 142, 150, as well as a tap node 146 implemented
as described herein. Further, such an autotransformer can be formed
by flip-mounting of one assembly (having a coil on a substrate) on
another assembly (having a coil on a substrate).
[0144] The resulting IPD 400 is shown to define a body 410 that can
include the first and second substrates 302, 312 associated with
the primary and secondary coils 304, 314. Such a body is shown to
include a first surface defined by a surface of the first substrate
302 opposite from the surface on which the primary coil 304 is
implemented, and a second surface defined by a surface of the
second substrate 312 opposite from the surface on which the
secondary coil 314 is implemented. When oriented in the example
manner as shown in FIG. 28, the first surface of the body 410 can
be a lower surface for mounting to, for example, a packaging
substrate of a module. The second surface of the body 410 can be an
upper surface that is substantially flat and suitable for mounting
of one or more components thereon. Examples of such mounting of
component(s) on the IPD 400, as well as associated advantages, are
described herein in greater detail.
[0145] FIG. 28 further shows that in some embodiments, appropriate
connections can be implemented in the IPD 400 to provide electrical
connections between the autotransformer 140 and contact locations
on the lower surface of the body 410. Such connections can allow
the IPD 400 to be mounted on another substrate, and also leave its
upper surface suitable for mounting of one or more components. For
example, conductive vias 402, 404, 406 through the first substrate
302 are shown to electrically connect the nodes 142, 146, 150 of
the autotransformer 140 with their respective contact locations on
the lower surface of the body 410. Although such connections are
depicted as direct through-substrate vias, it will be understood
that other connection configurations (e.g., through intermediate
metal layer(s), offset vias, etc.) can also be implemented.
[0146] FIG. 29 shows another example of an IPD 400 that is similar
to the example described in reference to FIGS. 19 and 20. The IPD
400 is shown to include an autotransformer 140 having primary and
secondary coils (e.g., traces) 304, 314 that are spaced apart by,
for example, an insulator layer such as a BCB layer. Such an
autotransformer can have its end nodes 142, 150, as well as a tap
node 146 implemented as described herein. Further, such an
autotransformer can be formed by flip-mounting of one assembly
(having a coil on a substrate) on another assembly (having a coil
on a substrate).
[0147] In the example of FIG. 29, the first substrate 302 can be a
packaging substrate such as a laminate substrate, and the second
substrate 312 can be a die substrate. Configured in the foregoing
manner, the coils of the autotransformer 140 can be positioned
above the surface of the laminate substrate 302. Such a
configuration can allow the laminate substrate to have a reduced
number of layers. Additionally, the die substrate with the
secondary coil being flip-mounted over the primary coil can allow
the backside of the die substrate to provide an upper surface that
is substantially flat and suitable for mounting of one or more
components thereon. Examples of such mounting of component(s) on
the IPD 400, as well as associated advantages, are described herein
in greater detail.
[0148] FIG. 30 depicts a side view of an IPD 400 similar to the
example of FIG. 28, with the autotransformer collectively indicated
as 140. The body 410 is shown to define a first surface 414 (e.g.,
a lower surface) on which contact pads 412 are formed so as to
facilitate mounting of the IPD 400 on another substrate. Such
contact pads can be electrically connected to the autotransformer
140 as described herein. The body 410 is shown to further define a
second surface 416 (e.g., an upper surface). As described herein,
such a surface can be suitable for mounting of one or more
components.
[0149] FIG. 31 shows a side view of an IPD 400 similar to the
example of FIG. 29, with the autotransformer collectively indicated
as 140. The IPD 400 is shown to include a primary coil 304 formed
on the surface of a packaging substrate 302 such as a laminate
substrate. A die substrate 312 with a secondary coil 314 formed
thereon is shown to be flip-mounted over the primary coil, with one
or more connection features between the coils 304, 314. An
insulator layer 330 is shown to generally fill the space between
the coils 304, 314 to provide, for example, desirable
autotransformer properties and support of the die substrate 312.
The die substrate 312 mounted in the foregoing manner is shown to
define a surface 416 (e.g., an upper surface). As described herein,
such a surface can be suitable for mounting of one or more
components.
[0150] Some of the examples of IPDs are described herein as having
one autotransformer. FIG. 32 shows that in some embodiments, more
than one autotransformer can be implemented in a given IPD. For
example, FIG. 32 depicts a side view of an IPD 400, with two
autotransformers 140a, 140b. Such two autotransformers can be
fabricated by, for example, arranging two primary traces on a
common first substrate, arranging two secondary traces on a common
second substrate, and flip-mounting one substrate on the other
substrate as described herein.
[0151] In the example of FIG. 32, the IPD 400 is shown to define a
second surface 416 (e.g., an upper surface). In some embodiments,
such an upper surface can be larger than the upper surface of the
examples of FIGS. 30 and 31, thereby providing a larger surface for
mounting of one or more components.
[0152] It will be understood that various IPDs described herein may
or may not include other circuit elements. Such circuit elements
can include those used to provide matching functionality on either
or both of the input and output sides of autotransformers.
[0153] FIGS. 33-39 show examples where one or more components are
mounted on an IPD having one or more features as described herein.
In some RF applications, it can be desirable to have a band
selection switch be relatively close to an output matching network
(OMN) associated with a power amplifier (PA). Such OMNs are
generally described herein in the context of matching circuits. In
some embodiments, such a band selection switch can be stacked over
an OMN that is implemented as an IPD to provide such proximity, as
well as to reduce the overall lateral area of a module.
[0154] FIG. 33 shows that an OMN implemented as an IPD 400 can be
mounted on a packaging substrate such as a laminate substrate 452,
and a band selection switch 460 can be stacked over the OMN IPD
400. FIGS. 34A and 34B show side and plan views of an example
configuration for the foregoing stack of the OMN IPD 400 and the
band selection switch 460, as well as electrical connections that
can be formed to facilitate various operations.
[0155] In FIG. 33, the OMN IPD 400 is shown to be mounted on the
laminate packaging substrate 452. The band selection switch 460 is
shown to be mounted on the OMN IPD 450. The OMN IPD 400 can be
configured in a number of ways, including, for example, flip-chip
configuration where electrical connections are generally made
through bump solders. Although described in the context of such a
flip-chip configuration, it will be understood that one or more
features of the present disclosure can also be implemented in other
configurations for the OMN IPD 400. The band selection switch 460
can be configured in a number of ways, including, for example, as a
die with wirebonding configuration where electrical connections are
generally made through wirebonds. Although described in the context
of such a wirebonding configuration, it will be understood that one
or more features of the present disclosure can also be implemented
in other die configurations for the band selection switch 460.
[0156] FIGS. 34A and 34B show side and plan views of an example
configuration 450 where connections among the band selection switch
460, the OMN IPD 400, and the laminate substrate 452 are
implemented as flip-chip connections and wirebonds. For example,
and as depicted in a simplified view of FIG. 34A, wirebonds 462 can
be formed between the band selection switch 460 and the laminate
substrate 452 to provide various electrical connections. For
example, the foregoing wirebond connections can be formed between
contact pads 464 formed on the band selection switch die 460 and
contact pads 466 formed on the laminate substrate 452. Electrical
connections and mechanical mounting functionality between the OMN
IPD 400 and the laminate substrate 452 can be provided by bump
solders 454.
[0157] In the example of FIGS. 33 and 34, the OMN being implemented
as an IPD as described herein allows mounting of a component such
as a band selection switch. As also described herein, such a
configuration provides advantages, including reduced space occupied
by such components, as well as providing close proximity between
the OMN and the band selection switch.
[0158] As described herein, the flip-chip or flip-mounted
configuration of the OMN IPD 400 can provide a relatively large
platform for stacking, for example a band switch die thereon. In
some embodiments, there may be sufficient space on such an OMN IPD
to stack another device aside from the band switch die.
[0159] FIGS. 35A and 35B show side and plan views of an example
configuration 450 where a band switch 460 is mounted on an OMN IPD
400, and an additional device is also mounted on the OMN IPD 400.
In some embodiments, such an additional device can include, for
example, a tuning circuit 480. Such a tuning circuit can include,
for example, harmonic tanks, and be implemented as a
duplexer-tuning IPD. Positioning such an IPD above the OMN device
provides additional space saving on the laminate substrate 452.
[0160] FIG. 36 shows an example of reduction in the lateral
dimensions of a module that can result from space savings provided
by stacking of component(s) as described herein. A module 500
having one or more features as described herein is compared to a
module 10 without such features. The module 10 is shown to have
lateral dimensions of d1'.times.d2'; while the module 500 is shown
to have reduced dimensions of d1.times.d2. For example, a
multimode, multiband (MMMB) PA module without the stacking features
as described herein can have lateral dimensions of approximately 5
mm.times.7 mm. A PA module implemented using one or more stacking
features as described herein can have lateral dimensions of
approximately 4 mm.times.7 mm, which is an approximately 20%
reduction in lateral size.
[0161] FIGS. 37 and 38 show another advantageous feature that can
result in modules having one or more features as described herein.
FIG. 37 shows an example configuration 20 without such features,
and FIG. 38 shows an example configuration 450 with such features.
More particularly, FIG. 37 shows a laminate substrate 12 having,
for example six laminate layers. As is generally understood, some
or all of matching network circuits can be implemented in one or
more of such laminate layers. Accordingly, an example output
matching network (OMN) 22 is depicted as being part of the laminate
substrate 12.
[0162] In FIG. 38, an OMN IPD 400 can be implemented on a laminate
substrate 452. Because such an OMN IPD can include some or all of
the components and/or functionalities associated with the
in-substrate portion of the OMN 22 (FIG. 37), amount of lateral
space and/or layers in the laminate substrate can be reduced. For
example, the laminate substrate 12 in the example of FIG. 37
includes six layers; while the laminate substrate 452 in the
example of FIG. 38 includes four layers. Such a significant
reduction in the number of laminate layers can provide a number of
advantages, including, reduction in height of the module and
reduction in costs associated with the module (e.g., cost
associated with the laminate substrate).
[0163] FIG. 39 depicts a block diagram of a module 500 that
includes one or more features as described herein. Such a module
can be configured to facilitate transmission and/or reception of RF
signals. The module 500 is shown to include a packaging substrate
452 configured to receive a plurality of components. Such a
packaging substrate can include, for example, a laminate
substrate.
[0164] The module 500 is shown to include a PA die 470 such as a
gallium arsenide (GaAs) die implemented in a heterojunction bipolar
transistor (HBT) process technology. Although described in the
context of HBT PAs, it will be understood that one or more features
of the present disclosure can also be implemented in other types of
PA die.
[0165] The module 500 is shown to further include a plurality of
output matching network (OMN) IPDs 400. As described herein, a band
switch circuit can be implemented and stacked over each of the OMN
IPDs 400. For example, a switch circuit die 460 is shown to be
stacked over each of the two OMN IPDs 400. In some embodiments, the
OMN IPDs 400 can be configured to provide matching functionality
for 3G/4G bands.
[0166] In some embodiments, the module 500 can further includes a
matching network device 530 for 2G bands.
[0167] In FIG. 39, a plurality of filter devices and a plurality of
duplexer devices are also shown to be mounted on the packaging
substrate 452. For example, band-pass filters and/or duplexers
indicated as blocks 504, 506, 510, 512, 516, 516, 518 and 520 are
shown to be mounted on the packaging substrate 452.
[0168] In some implementations, a device having one or more
features described herein can be included in an RF device such as a
wireless device. Such a device and/or a circuit can be implemented
directly in the wireless device, in a modular form as described
herein, or in some combination thereof. In some embodiments, such a
wireless device can include, for example, a cellular phone, a
smart-phone, a hand-held wireless device with or without phone
functionality, a wireless tablet, etc.
[0169] FIG. 40 depicts an example wireless device 600 having one or
more advantageous features described herein. In the context of a
matching circuit 400 having one or more features as described
herein, such a circuit (e.g., in a die form, an IPD form, modular
form, or some combination thereof) can be provided, for example, to
impedance match the outputs of a power amplifier (PA) module 616
having one or more PAs.
[0170] In the example wireless device 600, the PA module 614 can
provide an amplified RF signal to a switch 622 (via the matching
circuit 400 and a duplexer 620), and the switch 622 can route the
amplified RF signal to an antenna 624. The PA module 616 can
receive an unamplified RF signal from a transceiver 614 that can be
configured and operated in known manners.
[0171] The transceiver 614 can also be configured to process
received signals. Such received signals can be routed to one or
more LNAs (not shown) from the antenna 624, through the duplexer
620.
[0172] The transceiver 614 is shown to interact with a baseband
sub-system 610 that is configured to provide conversion between
data and/or voice signals suitable for a user and RF signals
suitable for the transceiver 614. The transceiver 614 is also shown
to be connected to a power management component 606 that is
configured to manage power for the operation of the wireless device
600.
[0173] The baseband sub-system 610 is shown to be connected to a
user interface 602 to facilitate various input and output of voice
and/or data provided to and received from the user. The baseband
sub-system 610 can also be connected to a memory 604 that is
configured to store data and/or instructions to facilitate the
operation of the wireless device, and/or to provide storage of
information for the user.
[0174] In some embodiments, one or more features of the present
disclosure can be implemented in a front-end module (FEM) 500. Such
a module can have different components depending on designs. For
example, the FEM 500 can include the PAs 614, the matching circuit
400, the duplexers 620, and the switch 622. It will be understood
that greater or lesser number of components can be included in such
a FEM.
[0175] A number of other wireless device configurations can utilize
one or more features described herein. For example, a wireless
device does not need to be a multi-band device. In another example,
a wireless device can include additional antennas such as diversity
antenna, and additional connectivity features such as Wi-Fi,
Bluetooth, and GPS.
[0176] Described herein are examples of how primary and secondary
metal traces can be implemented on an IPD, or on a packaging
substrate and an IPD die substrate. An autotransformer is an
example of how such primary and secondary metal traces can be
configured to provide a number of advantageous features. Although
the various examples herein are described in such an
autotransformer context, it will be understood that one or more
features associated with the primary and secondary metal traces can
also be implemented in other applications. For example, first and
second metal traces as described herein can also be implemented as
a general transformer, where the primary and secondary coils are
spaced from each other and not connected electrically. In such a
context, additional functionalities can be implemented. For
example, a tap connection can be provided on either of the primary
and secondary coils to sense a current flowing through the tapped
coil. Such a configuration can be utilized as, for example, a
monitor for power or current of an output of a device such as a
PA.
[0177] Further, it will be understood that while various examples
of the autotransformer-based matching circuits are described in the
context of IPDs, one or more active components or circuits can also
be incorporated into or be combined with such matching circuits.
Thus, one or more features of the present disclosure are not
necessarily limited to IPDs.
[0178] Unless the context clearly requires otherwise, throughout
the description and the claims, the words "comprise," "comprising,"
and the like are to be construed in an inclusive sense, as opposed
to an exclusive or exhaustive sense; that is to say, in the sense
of "including, but not limited to." The word "coupled", as
generally used herein, refers to two or more elements that may be
either directly connected, or connected by way of one or more
intermediate elements. Additionally, the words "herein," "above,"
"below," and words of similar import, when used in this
application, shall refer to this application as a whole and not to
any particular portions of this application. Where the context
permits, words in the above Detailed Description using the singular
or plural number may also include the plural or singular number
respectively. The word "or" in reference to a list of two or more
items, that word covers all of the following interpretations of the
word: any of the items in the list, all of the items in the list,
and any combination of the items in the list.
[0179] The above detailed description of embodiments of the
invention is not intended to be exhaustive or to limit the
invention to the precise form disclosed above. While specific
embodiments of, and examples for, the invention are described above
for illustrative purposes, various equivalent modifications are
possible within the scope of the invention, as those skilled in the
relevant art will recognize. For example, while processes or blocks
are presented in a given order, alternative embodiments may perform
routines having steps, or employ systems having blocks, in a
different order, and some processes or blocks may be deleted,
moved, added, subdivided, combined, and/or modified. Each of these
processes or blocks may be implemented in a variety of different
ways. Also, while processes or blocks are at times shown as being
performed in series, these processes or blocks may instead be
performed in parallel, or may be performed at different times.
[0180] The teachings of the invention provided herein can be
applied to other systems, not necessarily the system described
above. The elements and acts of the various embodiments described
above can be combined to provide further embodiments.
[0181] While certain embodiments of the inventions have been
described, these embodiments have been presented by way of example
only, and are not intended to limit the scope of the disclosure.
Indeed, the novel methods and systems described herein may be
embodied in a variety of other forms; furthermore, various
omissions, substitutions and changes in the form of the methods and
systems described herein may be made without departing from the
spirit of the disclosure. The accompanying claims and their
equivalents are intended to cover such forms or modifications as
would fall within the scope and spirit of the disclosure.
* * * * *