Application of Non-Linear Models in a Range of Challenging GaN HEMT Power Amplifier Designs
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Transcript of Application of Non-Linear Models in a Range of Challenging GaN HEMT Power Amplifier Designs
Application of NonApplication of Non--Linear Models in a Linear Models in a
range of challenging GaN HEMT Power range of challenging GaN HEMT Power
Amplifier Designs Amplifier Designs
Ray Pengelly, BradRay Pengelly, Brad MillonMillon, Don Farrell, , Don Farrell,
BillBill PribblePribble and Simon Woodand Simon Wood
WMC: Challenges in Model-Based HPA Design
Cree Inc., Research Triangle Park, NC 27709Cree Inc., Research Triangle Park, NC 27709
OutlineOutline
• Attributes of GaN HEMTs
• Cree GaN HEMT Models
• Design Examples
– Broadband CW Amplifiers
– Linear WiMAX Amplifier
• Future Model Improvements
• Conclusions
Attributes of GaNAttributes of GaN HEMTsHEMTs
• High Voltage Operation
• High power densities – 4 to 8 watts/mm at 28 and
50 volt operation respectively
• High Frequency Performance – present Cree process has fT of 25 GHz
• High Efficiency
• Low Quiescent Current
• High Native Linearity
• Low capacitance per peak watt (12% of LDMOS and 21% ofGaAs MESFET) – supports broad bandwidths
• Enable new amplifier architectures
• Highly correctable under DPD
• Almost constant CDS as a function of VDS – great for Drain Modulation
WideBan
dgap
Models for GaNModels for GaN HEMTsHEMTs
• Equivalent-circuit based approach
– Relatively simple extraction
– Process sensitive based on individual elements
– Simple implementation using commercial harmonic balance simulators
• Significant historical information for model basis and validation
• Non-linearity introduced as required by element
– Drain current source is dominant non-linearity
– Gate current formulation includes breakdown and forward conduction
– Voltage variations of parasitic capacitances derived from charge formulations
• Model data fit extends over drive, frequency, bias, and temperature
• Many hundreds of successful hybrid and MMIC designs
Model SchematicModel Schematic
vd1g
vg1
Port
P2
Num=2
SRL
SRL4
L=(ld/sc+ld1/(sc*scf)) nH
R=(rd/(sc*scf)) Ohm
R
R6
R=1e6 Ohm
pncap3X15
vgg0=-21 V
cg3=0.1
cg2=0.6
cg1=cgd pF
scf=scf
sc=sc
R
R3
R=0.01 Ohm
SRL
SRL1
L=(lg/sc+lg1/(scf*sc)) nH
R=(rg/sc+rg1/(sc*scf)) Ohm
pncap3
X12
vgg0=vgg0 V
cg3=cg3
cg2=cg2
cg1=cgs pF
scf=scfsc=sc
Port
P1
Num=1
R
R1
R=(ri/(sc*scf)) Ohm
Port
P5
Num=5
SRLSRL3
R=(rs/(sc*scf)) Ohm
L=(ls/sc) nH
Port
P4
Num=4
C
C8
C=30.0 nF
R
R2
R=rth Ohm
VCVS
SRC1
G=1
Port
P8
Num=8
C
C7
C=1.0 uF
R
R5R=1e6 Ohm
C
C9
C=(cds*sc*scf) pF
SDD6P
SDD6P1
Cport[1]=
C[1]=I[6,0]=(vdf)/5e4
I[5,0]=-vd*idt
I[4,0]=(_v4)*gmc
I[3,0]=(_v3)*gdsc
I[2,0]=id1
I[1,0]=(vg)/5e8
• Based on 13-element MESFET model (H. Kondoh – 1986 MTT-S)
• ADS version shown using non-linear equation-based elements
– Easily changed during design process
– Speed comparable to C-coded version
• AWR version uses C code with “model wizard”
Drain current
Thermal resistance
More details on More details on GaNGaN HEMT ModelHEMT Model
• Most FET models implement a gate current-control characteristic that transitions from the sub-threshold region to the linear gate control region directly, without treating the intermediate region, called the quadratic region. Fager et al. implemented an equation and new parameters to fit the quadratic region. This leads to better agreement with measured IMD and other nonlinear characteristics.
• Gate charge is partitioned into gate-source and gate-drain charge. Each charge expression is a function of both VDS and VGS. Using charge partitioning, it is possible to fit most GaN HEMT capacitance functions and observed charge conservation.
-15 -10 -5 0 5 8
Voltage (V)
gm and Ids
0
5
10
15
20
25
30
0
666.7
1333
2000
2667
3333
4000
p1
|S(2,1)|[1,X] (L)Schematic 1
IDC(I_METER.AMP1) (R, mA)Schematic 1
p1: Freq = 0.05 GHz
Sub
Threshold
Blue is DC transconductance
Red is drain current
Quad Linear Compression
Ids, mA
Gate voltage, volts
Gm, mS500
250
0-4 -3 -2 -1 0 0.5
• The model includes new capacitance functions as well as modeling of the drain-source breakdown and self heating.
• The model has four ports, with the extra port providing a measure of the temperature rise. The voltage between the external thermal circuit port and the source node is numerically equal to the junction temperature rise in degrees C. This occurs because the current source in the thermal circuit is numerically equal to the instantaneous power dissipated in the FET and the resistance, R_TH is numerically equal to the thermal resistance. The RC product of the thermal circuit is the thermal time constant.
• The model addresses the sharp turn-on knee in GaN HEMTs leading to the accurate prediction of IMD sweet spots in Class A/B operation.
More details on More details on GaNGaN HEMT ModelHEMT Model
Drain Current ModelDrain Current Model
-3 -2 -1 0 1-4 2
0.05
0.10
0.00
0.15
Vlow
gm
5 10 15 20 25 30 35 400 45
0.1
0.2
0.3
0.4
0.0
0.5
Vhigh
perm
ute(Is_high.i)
• Transconductance curve fit to Gm from small-signal model fits over bias range
• Output conductance dispersion model
• Peak current and knee voltage fit from load-pull - includes trap effects
• Pinch-off fit from DC IV-characteristics – gives model of drain current
• IV function similar to Fager-Statz formulation – good model of pinch-off needed to accurately predict intermodulation distortion
Temperature Dependence Temperature Dependence –– SelfSelf--heatingheating
34
34.5
35
35.5
36
36.5
0 50 100 150 200
chuck temp
output power
• Drain current is only temperature dependent model element
• Drain current scales to provide -0.1 dB/10oC reduction in power for current-limited load-line
• Self-heating included using a thermal resistance – calculated from finite element analysis of die and package.
• Thermal performance due to package needs to be included where appropriate
1mm gate width
Feedback Capacitance Feedback Capacitance -- CCGDGD
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0 10 20 30 40 50 60
Drain Voltage
Feedback Capacitance Cgd (pF)
• Feedback capacitance is a strong function of drain voltage
• Inclusion of this effect necessary to fit small-signal data
• Non-linearity changes harmonic generation from the model – effects efficiency and linearity predictions
• Output Capacitance CDS is linear – no voltage dependence (weak anyway)
Input Capacitance Input Capacitance -- CCGSGS
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
-3.5 -3 -2.5 -2 -1.5 -1 -0.5 0
Gate Voltage (V)
Input Capacitance Cgs (pF)
• Input capacitance is a strong function of gate voltage
• CGS is also a function of drain voltage, but this non-linearity is not included at present
• The gate-voltage non-linearity also effects model’s harmonic generation
GaN HEMT Model GaN HEMT Model -- SmallSmall--SignalSignal
• On-wafer S-parameters of 0.5 mm HEMT – 25OC baseplate
• Major challenge of modeling for high power circuits – scaling from reasonable test cell to large periphery output stages – successfully implemented for scaling factors >100:1
• Non-linear model fits small-signal parameters over a range of bias voltages
• All measurements performed using 1% duty cycle, 20µs pulsed bias to control thermal effects
ModelGmax
MeasuredGmax
measured
model
freq (1.000GHz to 14.00GHz)
a(1,1)
b(1,1)
b(2,2)
a(2,2)
1E101E9 2E10
15
20
25
10
30
freq, Hz
ag
bg
GaN HEMT Model GaN HEMT Model -- LargeLarge--SignalSignal
measured
model
• On-wafer load-pull of 0.5 mm HEMT
• Measured at 3.5 GHz, VDS=48V, Id~25%IDSS, 25OC chuck temperature
• PAE contours not used for modeling due to sensitivity to harmonic loading –PAE verified using hybrid amplifier measurements
Power Contour Levels:
36 dBm
35 dBm
34 dBm
Basic Thermal Features of High Voltage GaNBasic Thermal Features of High Voltage GaN
• 240 Watts CW RF from a 28.8mm HEMT operating at 50 volts drain voltage
• Assume 60% DC to RF conversion efficiency
• 160 watts dissipated heat
• Active chip area is 2.5 sq. mm so heat density is
> 40 kilowatts per square inch !
• Much emphasis on new amplifier architectures to improve drain efficiencies
Broadband Amplifier Performance Broadband Amplifier Performance
TradeTrade--Off Analysis Off Analysis -- BackgroundBackground
• Broadband (0.8 to 2.2 GHz) push-pull amplifier to provide 100 watts peak power
• Two GaN HEMT die in “Gemini”package
– HEMTs attached to composite material shims within Cu-Mo-Cu package
• Study drain efficiencies over the band and impact on thermal management
– Comparison of different matching approaches and termination impedances
Theta-jc is 1.1 deg C/watt
Basic Amplifier Basic Amplifier
• Different matching topologies
– Drain-to-Gate Feedback
– Lossy Match
– Multi-section reactive
– Lossy Match with Feedback
• Concentrate on Lossy Match case
Power=10
1 2
SUBCKTID=S3NET="GaN HEMT Die Model G3"
1 2
3
SUBCKTID=S2NET="OMN Lossy Match"
1 2
3
SUBCKTID=S1NET="IMN Lossy Match"
Xo Xn. . .
SWPVARID=SWP4VarName="Power"Values=stepped(10,40,.1)UnitType=None
ATTENID=U1R=50 OhmLOSS=3 dB
DCVSID=V2V=2.2 V
I_METERID=AMP1
DCVSID=V1V=28 V
PORT1P=1Z=50 OhmPwr=Power dBm
PORTP=2Z=50 Ohm
PORTP=3Z=50 Ohm
PORTP=2Z=50 Ohm
PORTP=1Z=50 Ohm
CAPID=C1C=2.271 pF
TLINID=TL8Z0=9.149 OhmEL=42.65 DegF0=1.5 GHz
TLINID=TL7Z0=28.29 OhmEL=57.64 DegF0=1.5 GHz
TLINID=TL6Z0=43.09 OhmEL=195.3 DegF0=1.5 GHz
CAPID=C8C=2.414 pF
CAPID=C7C=1.243 pF
DC
RFRF&DC
12
3
BIASTEEID=X1
Overall Schematic
Input Match Schematic
PORTP=3Z=50 Ohm
PORTP=2Z=50 Ohm
PORTP=1Z=50 Ohm
TLINID=TL5Z0=35.25 OhmEL=93.57 DegF0=1.5 GHz
TLINID=TL4Z0=18.75 OhmEL=86.31 DegF0=1.5 GHz
TLINID=TL3Z0=10.16 OhmEL=70.63 DegF0=1.5 GHz
CAPID=C5C=0.6011 pF
CAPID=C4C=1.006 pF
DC
RFRF&DC
1 2
3
BIASTEEID=X1
Output Match Schematic
Simulated Amplifier PerformanceSimulated Amplifier Performance
Small Signal Gain
Output Power at P3dB and Drain Efficiency
POUT
Efficiency
Gain = 13.2 dB ± 0.8 dB
POUT = 46 to 59 wattsDrain Efficiency = 49 to 66%Worst Case Dissipated Heat is 54 watts(per transistor)
Thermal PerformanceThermal Performance
• Assuming TJ limit of 200OC,
maximum dissipated heat of 108 watts and theta-jc of 1.1 deg C/Watt leads to a maximum case temperature of 81 deg C
• The thermal characteristics of the die and the package are very important – The design requires a
composite material shim such as silver-diamond (theta jc=550 W/mK) mounted on a Super-CMC package flange (theta jc = 370 W/mK)
• Before full electrical design is completed broadband amplifiers require thermal design even with GaN HEMTs!
Pdiss
0
0.5
1
1.5
2
2.5
3
3.5
4
0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1 2.3
Frequency (GHz)
Pdiss (W/mm)
Pdiss LossyMatch
3.75 W/mm dissipated54 watts per transistor
Dissipated Power as a function of frequency
Comparison of Dissipated Power vs. Comparison of Dissipated Power vs.
Frequency for 4 Amplifier ApproachesFrequency for 4 Amplifier Approaches
• Large-Signal Modeling of Broadband Amplifiers invaluable in selecting optimum topology for both electrical and thermal performance
Pdiss
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1 2.3
Frequency (GHz)
Pdiss (W/mm)
PdissMultisection
Pdiss LossyMatch
Pdiss LM wFeedback
Pdiss MS wFeedback
Multi-section reactive
Lossy match with feedback
Lossy MatchFeedback
Drain Efficiency at Device Sat
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
0.000 0.500 1.000 1.500 2.000 2.500 3.000
Frequency (GHz)
Drain Efficiency (%)
Power out at Device Sat (W)
0.00
20.00
40.00
60.00
80.00
100.00
120.00
0.000 0.500 1.000 1.500 2.000 2.500 3.000
Frequency (GHz)
Psat (W)
Measured 0.5 to 2.5 GHz PushMeasured 0.5 to 2.5 GHz Push--Pull Pull
Amplifier PerformanceAmplifier Performance
25 to 50 ohm coupler
Full amplifier with
coupler insertion losses
Average Gain = 15 dB
Psat > 80 watts and
Drain Efficiencies > 45%
500 to 2700 MHz Amplifier 500 to 2700 MHz Amplifier
using Cree CGH40010Fusing Cree CGH40010F
CAPID=C1C=15.55 pF
CAPID=C2C=1.187 pF
CAPID=C3C=0.9191 pF
CAPID=C4C=1.096 pF
CAPID=C5C=8.513 pF
1
2
3
CGH40010F_r2ID=40010F1TNOM=105
DCVSID=V1V=2.05 V
DCVSID=V2V=28 V
INDID=L1L=200 nH
INDID=L2L=200 nH
I_METERID=AMP1
PIPADID=P1Z1=50 OhmZ2=50 OhmDB=2 dB
RESID=R1R=51 Ohm
RESID=R2R=0 Ohm
TLINID=TL1Z0=70.11 OhmEL=32.91 DegF0=3 GHz
TLINID=TL2Z0=12.22 OhmEL=21.88 DegF0=3 GHz
TLINID=TL3Z0=53.79 OhmEL=26.09 DegF0=3 GHz
PORT_PS1P=1Z=50 OhmPStart=-8 dBmPStop=32 dBmPStep=5 dB PORT
P=2Z=50 Ohm
Lossy Match
Simulated Performance of Simulated Performance of
500 to 2700 MHz GaN HEMT PA500 to 2700 MHz GaN HEMT PA
0.5 1 1.5 2 2.5 2.7
Frequency (GHz)
Small Signal S21 S11 and S22
-30
-20
-10
0
10
20
30
dB
p3
p2
p1
DB(|S(1,1)|)[X,2]500 to 2700 MHz Stage
DB(|S(2,1)|)[X,2]500 to 2700 MHz Stage
DB(|S(2,2)|)[X,2]500 to 2700 MHz Stage
p1: Pwr = -3 dBm
p2: Pwr = -3 dBm
p3: Pwr = -3 dBm
-8 2 12 22 32
Input Power (dBm)
POUT and Efficiency Vs Input Power
0
20
40
60
80
dBm and %
DCRF(PORT_ 2 )[ *, X]
Re a l Ci rc u i t
DB(PT (PORT_2 ))[ *,X] (d Bm )
5 0 0 to 2 70 0 M Hz Sta g e
DCRF(PORT_ 2 )[ *, X]
5 0 0 to 2 70 0 M Hz Sta g e
DB(PT (PORT_2 ))[ *,X]
Re a l Ci rc u i t
• Worst Case Heat Dissipation is 9 watts• Theta-jc of packaged transistor is 5 deg C/watt• Max. channel temperature at 85 deg C case is 130 deg C.
Measured Performance of Measured Performance of
500 to 2700 MHz GaN HEMT PA500 to 2700 MHz GaN HEMT PA
0.5 1 1.5 2 2.5 2.7
Frequency (GHz)
Simulated Vs Actual
-10
-5
0
5
10
15
20
dB
p6
p5
p4p3
p2
p1
p1: Pwr = -3 dBm p2: Pwr = -3 dBm p3: Pwr = -3 dBm
p4: Pwr = -3 dBm p5: Pwr = -3 dBm p6: Pwr = -3 dBm
Output Power
20
22
24
26
28
30
32
34
36
38
40
42
44
10 12 14 16 18 20 22 24 26 28 30 32 34
PIN (dBm)
POUT (dBm)
0.25 GHz
0.50 GHz
0.75 GHz
1.00 GHz
1.25 GHz
1.50 GHz
1.75 GHz
2.00 GHz
2.25 GHz
2.50 GHz
2.70 GHz
3.00 GHz
Saturated Output Power and Drain Efficiency
363840424446485052545658606264666870727476788082
0 0.25 0.5 0.75 1 1.25 1.5 1.75 2 2.25 2.5 2.75 3 3.25
Frequency (GHz)
POUT (dBm) / Efficiency (%)
PSAT
EFFICIENCY @PSAT
• Excellent agreement betweensimulations and measurements
• Measured efficiencies between50 and 78% over the band
Efficiency
Power
Output Power vs. Frequency
Saturated Output Power and Efficiency
Simulated and measured
Linear WiMAX AmplifierLinear WiMAX Amplifier
Simulation versus Measured DataSimulation versus Measured Data
• 60 Watt, 2.3 to 2.8 GHz linear amplifier design
• Developed an accurate packaged transistor model using the Cree GaN HEMT scale-able die model
• Circuit developed to address Fixed and Mobile Access WiMAX applications such as
– 802.16-2004
– 802.16e
– WiBro
• The design targets were as follows:
– Average Output Power > 8W
– EVM < 2.5%
– Drain Efficiency > 25% (under WiMAX stimulus)
CAPID=C2C=0.06 pF
CAPID=C3C=0.06 pF
CAPID=CDpad1C=0.48 pF
MLINID=TL1W=250 milL=60 mil
MSUBEr=9.6H=20 milT=1.4 milRho=1Tand=0ErNom=9.6Name=Alum_pkg1
SRLID=RLD1R=0.007 OhmL=0.285 nH
CAPID=C1C=0.06 pF
CAPID=C4C=0.06 pF
CAPID=CDpad2C=0.48 pF
MLINID=TL2W=250 milL=60 mil
SRLID=RLD2R=0.007 OhmL=Lbond nH
CAPID=C5C=0.03 pF
1
2
3
GaNg28v2_r3ID=GaNv2sc1TNOM=25SC=20SCF=1.44RTH=2.7VDD=50
SRLID=RL1R=0.001 OhmL=0.015 nH
V_METERID=VM1
PORTP=5Z=50 Ohm
PORTP=6Z=50 Ohm
CGH27060F Packaged Device ModelCGH27060F Packaged Device Model
1
2
3
CGH40045F_r1ID=CGH27030TNOM=25
ID=CGH27060TNOM=25
Input Circuit ModelInput Circuit Model
PORTP=1Z=50 O hm
PORTP=2Z= 50 Ohm
1 2
3
SUBCK TID=S3NET="G ate Pad 3 Por t"
1 2
SUBCKTID=S4NE T="Input Launch_AS TUNED"
1
SUBCKTID=S8NET= "Input_S hunt_GND_03_21_071"
1 2
3
4 SUBCKTID=S5NET="Input Tank Junction_EM1"
1
SUBCKTID=S 2NET="Gate B ias Feed w ith T rans Line_02_06_06"
1 2
SUBCKTID=S1NET= "S tabil ity C ircuit_New"
MLINID=TL_S HW =20 milL=230 m il
MDLX1 2
MODcatc0603001ID=ATC_600S _C1C=0.85 pFMSUB=Sim_mode= 0Tolerance=1PADW =35 m il
MLE FID=OpenW=30 milL=93 m il
MSUBEr=3.66H=20 m ilT=1.4 m ilRho=1Tand=0.004ErNom=3.48Name=Rogers 1
M STEP$ID=TL1 5
MSTEP$ID=TL14
M LINID=T L1 3W =7 0 milL =200 m il
MLINID=TL12W =20 mi lL= 130 m il
M LINID=T L11W =7 0 milL =200 mi l MSTEP$
ID=TL10M STEP$ID=T L9
MSTEP$ID=TL8
MSU B
Er=3.66H= 20 m ilT=1.4 milRh o=1Tand=0.004ErNom=3.66Na me=Roge rs 1
MLINID=T L4W =44 milL=565 m il
M LINID =T L2W =1 0 milL =120 mi l
MLI NID=TL1W =44 mi lL= 25 m il
PORTP=2Z=50 Ohm
PORTP=1Z=50 Ohm
PORTP=2Z=50 Ohm
1
2
3
SUBCKTID=S1NET="Induct ive L ine_2p5_New1"
MLINID=T L1W=35 m ilL=23 m il
1
2
3
SUBCKTID=S2NET=" Induc tive Line_2p5_New1"
MDLX1 2
MODcatc 0603001ID=ATC _600S_C1C=2.2 pFMSUB=Sim _m ode=0Tolerance=1PADW =35 mil
PORTP=1Z =50 Ohm
MDLX
1 2
SU BCKTID=S3NET="Resis tor_100_Ohm Center1"
M STEP$ID=TL8
MLINID=TL5W=44 milL=25 m il
MLINID=TL4W =10 milL=40 mil
MLINID=T L3W=10 m ilL=40 m il
MSUBE r=3.66H =20 milT =1.4 milR ho=1T and=0.004E rNom=3.66N ame=R ogers 1
MLINID=TL2W =35 milL=23 mil
2
13
Output Circuit ModelOutput Circuit Model
M L INID = T L3
W =W o ut m i lL = L o ut m i l
ML IN
ID= T L 2W =W o u t mi l
L =5 0 m il
M BEND 90 X
ID= M S4W =Wo u t mi l
M =0 .5
M L IN
ID = TL 1 7W = 48 m ilL = 1 2 mi l
ML IN
ID = T L1 5W= 70 m i l
L=2 0 0 m i l
M STEP$ID= TL 1 4
M STEP$
ID= TL 1 3
M STEP$ID =TL 1 2
M STEP$
ID =TL 4
M LIN
ID= Db i a sL 3W=W b i a s m i l
L = Lb i a s m i l
M BEN D9 0 X
ID = MS6W =W b ia s mi l
M = 0 .5
ML IN
ID = Db i as L 2W=W b ia s mi l
L= L b i as m il
M BEN D9 0 XID = MS1W =W b ia s mi l
M = 0 .5
ML INID = Db i as L 1
W =Wb ia s mi lL= 2 4 0 m i l ML IN
ID = T L1 1W= 70 m i l
L= 2 0 0 m i l
M LIN
ID= T L 1 0W= 2 0 mi l
L = 1 30 m il
M LIN
ID= T L 1W= 4 4 mi l
L =1 44 m il
M LINID= T L 8
W =W o u t mi lL = 45 m i l
M L INID= T L 7
W =W o u t m ilL = L ou t m il
M LIN
ID= T L 5W =W o u t mi l
L = 44 m il
1
SU BCKT
ID= S1NE T= " Dra in Bi a s T e rm i na ti o n"
1
SUBC KTID= S5
NET = "D rai n B ias T e rm in a t io n "
ML EFID = OStu b 2W = 11 0 m il
L= 3 0 mi l
M L EF
ID= O Stu b6W = 7 2 mi l
L = 2 6 m i l
1
SU BCKTID= S6
NE T =" Ha rmo n i c As s is t_ AS T UN ED"
1 2
3
4SU BCKTID =S 2N ET= "Dra i n P ad 4 Po rt_2 p 5 "
M L EF
ID= O Stu b1W = 1 1 0 mi l
L = 3 0 m i l
M LIN
ID= T L 2 0W = 1 1 0 m i l
L = 2 m i l
MS TE P$
ID= TL 19M L IN
ID =T L 1 6W =1 6 0 mi l
L = 2 6 5 m i l
M DL X1 2
M OD ca tc 10 0 B0 0 1ID= ATC _1 0 0 B_ C1
C= 8 .2 pFM SUB=
Sim _m o d e= 0To l era n c e= 1
PAD W = 1 10 m il
M L EFID= O Stu b5W= 7 2 mi l
L = 2 6 m i l
1
2
3
4
M CR OSS$ID =T L 1 8
M SUBEr=3 .6 6
H =2 0 m ilT =1 .4 m i l
R ho = 1T a n d =0 .0 0 4ErN o m= 3 .4 8
N am e = Ro g ers 4 3 50
M BEND 90 XID= M S3
W =W o u t mi lM = 0.5
M BEND 90 X
ID= M S2W =W o u t mi l
M = 0.5
M L EFID =O Stu b 4
W =4 0 m ilL = 1 7 4 m i l
1
2
3
4
M CR OSS$ID =T L 9
M LIN
ID= T L 6W = 3 4 mi l
L = 60 m il
M L EFID =O Stu b 3
W =4 0 m ilL =1 7 4 m i l
ML INID= Db i a sL
W =W b i as m ilL =2 4 0 mi l
1 2
SUBC KTID= S3
NET = "D rai n B l o ck Ca p Pa d_ 2 p 5 "1
2
3SU BCKTID= S7
NE T= " 3p o rt_ co rn e r"
PO RTP=1Z =5 0 O hm
P ORT
P = 2Z = 5 0 Oh m
L stu b _ M= 7 0
Wo u t= 34
W d l in e = 1 00
L o ut= 6 1
L b ia s = 25 5W b i as = 4 0
L stu b _ A= 50
1
2
3
4
Fully Modeled Layout of AmplifierFully Modeled Layout of Amplifier
J3
LC
9 478 56 3 2 1
J2
J1
Actual Printed Circuit Board
Simulated and Measured AmplifierSimulated and Measured Amplifier
1.8 1.9 2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3 3.1 3.2
Frequency (GHz)
Small Signal Frequency Response
5
6
7
8
9
10
11
12
13
14
15
Small Signal G
ain (dB)
-15
-13
-11
-9
-7
-5
-3
-1
1
3
5
Return Loss (dB)
DB(|S(1,1)|) (R)Amp_SS_AsTuned
DB(|S(2,1)|) (L)Amp_SS_AsTuned
DB(|S(2,1)|) (L)fixt20_G28V2144L1w3__5
DB(|S(1,1)|) (R)fixt20_G28V2144L1w3__5
DB(|S(2,2)|) (R)Amp_SS_AsTuned
Simulated Linearity of AmplifierSimulated Linearity of Amplifier
26 28 30 32 34 36 38 40 42 44 46
2 Tone Average Output Power (dBm)
2-Tone IMD vs Average Ouput Power
-60
-50
-40
-30
-20
-10
0
3rd & 5th Order IMD (dBc)
0
10
20
30
40
50
60
Drain Efficiency (%)
IM3L_Pave (L)
IM3U_Pave (L)
IM5L_Pave (L)
IM5U_Pave (L)
DE_Pave (R)
Measured Linearity of AmplifierMeasured Linearity of Amplifier
EVM and Efficiency vs. Average Output Power
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
22.0 24.0 26.0 28.0 30.0 32.0 34.0 36.0 38.0 40.0 42.0
Average Output Power (dBm)
EVM (%)
0.0%
5.0%
10.0%
15.0%
20.0%
25.0%
30.0%
35.0%
40.0%
Drain Efficiency (%)
EVM 2.5GHz
DE 2.5GHz
Measured Linearity of AmplifierMeasured Linearity of Amplifier
EVM and Efficiency vs Frequency
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
2.300 2.400 2.500 2.600 2.700
Frequency (GHz)
EVM (%)
0.0%
5.0%
10.0%
15.0%
20.0%
25.0%
30.0%
35.0%
40.0%
Drain Efficiency (%)
EVM @ 26dBm
EVM @ 39dBm
Efficiency @ 2.5% EVM
Future GaN HEMT Future GaN HEMT
Model ImprovementsModel Improvements
• Behavioral models to allow direct simulation of various digital waveforms
• Improved active and passive switch models
• Improved models for switch mode PA’s
• Additional noise models
• Support for simulators other than ADS and MWO
Conclusions
• Successful development of GaN HEMT
large-signal models
• Models are scale-able over > 100:1 gate width ratio
• Models
– Are broadband
– Accurately predict DC, s-parameters, dynamic load lines, non-linearities
– Include self-heating
– Can be used in a range of amplifier types
• Demonstrated a variety of hybrid circuit applications
• Equally useful for MMIC amplifier designs
• Future extensions to include other features such as noise