Broadband GaN MMICs: Multi-Octave Bandwidth PAs to Multi-Watt Linear LNAs Kevin W. Kobayashi and Karthik Krishnamurthy 2012 PA Symposium, La Jolla Cove California Good Morning! Page 2 La Jolla Cove California Page 2 OUTLINE • Need: BW, Power, Linearity, PAE, Sensitivity, Survivability • Broadband Application • GaN Flavors (fT, Lg, BVdg, LN, Power Density) • Broadband Amplifier Topology – Trades • Cascode FB • Darlington FB • Lossy Match • DA and NDPA • Recent Results • Summary & Future Directions Page 3 GaN Enables Broadband Front-End Performance wide band-gap Linearity Power/Efficiency Spectral Efficiency Multi-band electron velocity Bandwidth Sensitivity (Low NF) 2-D Gas Channel Network Reach Page 4 > Decade BW bigger pipe-line Power Frequency (PF2) Limit Pmax Eg4 v 2 s F 2 Maximum Power (Watts) 100,000.0 10,000.0 Property Si GaAs GaN Eg (eV) 1.1 1.4 3.4 vs (10 7 cm/s) 0.7 0.8 2.5 X-Band Military Radar Commercial Satcom Transmitters (VSAT - 1MBPS) 1,000.0 Commercial Broadband Satcom (VSAT - 16MBPS) 100.0 10.0 Point to Point millimeter wave radios Commercial Communications Base Stations sensing and imaging 1.0 0.1 1 10 100 Frequency (GHz) Page 5 IMS 2010 WE4E-5 OUTLINE • Need: BW, Power, Linearity, PAE, Sensitivity, Survivability • Broadband Application • GaN Flavors (fT, Lg, BVdg, LN, Power Density) • Broadband Amplifier Topology – Trades • Cascode FB • Darlington FB • Lossy Match • DA and NDPA • Recent Results • Summary & Future Directions Page 6 Example: SDR need for broadband / efficiency • Emerging Software Defined Radio Architectures Joint Tactical Radio Systems (JTRS) Public Mobile Radio 30 MHz 1 10 100 Frequency (MHz) 2000 MHz 1000 10000 • Requirements - Multi-decade bandwidth (30MHz - 2 GHz) - Medium power (10W and higher) - Multi-band / multi-standard operation - Reconfigurable hardware Page 7 2009 SDR Forum Example: GaN Device CATV Need for Decade BW Linearity GaN Power Doubler Amplifier Typical NTSC CATV Spectrum Block Diagram Courtesy Rainer Hillermeier - RFMD CATV requires > 67 dBc C/I beyond 1 GHz to support analog, HDTV, VOD, & high speed internet Page 8 BCTM 2009, Shealy et.al. OUTLINE • Need: BW, Power, Linearity, PAE, Sensitivity, Survivability • Broadband Application • GaN Flavors (fT, Lg, BVdg, LN, Power Density) • Broadband Amplifier Topology – Trades • Cascode FB • Darlington FB • Lossy Match • DA and NDPA • Recent Results • Summary & Future Directions Page 9 Flavors of Microwave GaN HEMT MMIC Technology Passives HEMT Device GaN Short Lg MMIC Technologies – Recent Literature (0.1um-0.25um) Page 10 Parameter Units TQNT [1,2] TQNT [ 3] Northrop Grumman [ 4] Fraunhofer Institute [ 5] HRL [ 6] Intended Frequency GHz Ku-band Ka-band Ka-band Ka-band W-band Gate Length um 0.25 0.15 0.25 0.1 0.14 T-gate T-gate T-gate Gate Structure Field Plate Imax mA/mm 900 1150 1050 1300 1200 Gm mS/mm 300 380 300 550 381 Vbd V 70 > 50 75 Practical Operating Vds V 30 20 20-28 15 10-14 fT/fmax GHz 29 56 >80/200 97/230 Power Density W/mm 5-8 @ 10GHz ~4 2-4 Backside Vias - Yes Yes Yes Yes MIC Caps - 3 1 1 TFR Resistors - TaN Interconnect - 3 2 2 Wafer thickness um 100 100 75 Commercial Qual - YES 100 YES ~1.8 Yes 50 OUTLINE • Need: BW, Power, Linearity, PAE, Sensitivity, Survivability • Broadband Application • GaN Flavors (fT, Lg, BVdg, LN, Power Density) • Broadband Amplifier Topology – Trades • Cascode FB • Darlington FB • Lossy Match • DA and NDPA • Recent Results • Summary & Future Directions Page 11 Multi-Octave BW MMIC GaN Amplifier Topology Consideration Highlights Cascode FB BW Linearity 2nd Order Linearity CSO-BW Proven NF Good NFBW Efficiency Page 12 LossyMatch 1.5*fT capability Great IP3/IP2BW Thermal Mitigation Darlington FB fT-doubler Great Great Po-BW Great IP3-BW Actively limited DA & NDPA Passively limited Passively limited > 40% PAE Up to 40% PAE flexible flexible More Voltage More Current Cascode • Cascode • Reduces Miller Capacitance – better BW • Increased output impedance – better linearity BW • Stacked devices – higher Vdd • Spread devices – lower Tj • Breaks thermal electric feedback in BJTs • noisier, unstable, and less linear power efficient (I-V knee) Page 13 Cascode – Higher Voltage & Power Operation Performance Practical Vdd Commonsource Cascode/*Dual gate 20V (T-gate) 40V Pout , IP3 Page 14 4-6 dB improvement Idd 250mA/mm same Tj @ 85C base ~200C ~*200C NF higher (id1_n,id2_n) BW much wider Gain much higher, flatter Stability poorer IMS 2012 WS: WFE Cascode Electrical Characteristics I-V characteristics Maximum Available Gain A/mm Wg = 500um HEMT 50 1.2 COMMON-SOURCE CASCODE Max Gain (dB) IDS (A/mm) 1.0 0.8 0.6 0.4 0.2 40 CASCODE 30 20 10 COMMON-SOURCE 0 0.0 0 10 20 30 40 50 60 70 80 0 VDS Cascode has higher Ro, good IP3 But higher Vknee, poorer PAE *Tj~200C @ 20V-250mA/mm Page 15 IMS 2012 WS: WFE 10 20 30 40 50 60 70 80 90 100 Frequency (GHz) Cascode has higher MAG but less stable Cascode vs. CS Output Characteristics Common-Source Cascode m4 freq=11.01 S(1,1)=0.8 impedance m5 freq=11.01GHz S(3,3)=0.827 / -123.994 impedance = Z0 * (0.121 - j0.526) m5 freq=11.01 S(3,3)=0.8 impedance S(4,4) S(3,3) S(2,2) S(1,1) Cout ~ 0.8 pF/mm S22 S11 m7 m6 m5 m4 Cin ~ 1.5 pF/mm freq (10.00MHz to 20.00GHz) S(4,4) S(3,3) S(2,2) S(1,1) m4 freq=11.01GHz S(1,1)=0.829 / -119.769 impedance = Z0 * (0.125 - j0.573) Cout ~ 0.16 pF/mm m6 freq=11.01GHz S(2,2)=0.408 / -65.397 impedance = Z0 * (1.008 - j0.898) S22 m7 freq=11.01GHz S(4,4)=0.394 / -62.568 impedance = Z0 * (1.066 - j0.884) m4 m5 S11 Cin ~ 1.1 pF/mm freq (10.00MHz to 20.00GHz) Cascode has ~ 1/5th the output capacitance than a CS Page 16 m6 m7 m6 freq=11.01 S(2,2)=0.9 impedance m7 freq=11.01 S(4,4)=0.9 impedance Cascode -Thermal Mitigation + Vds2 - + Vds1 - Tj ~ 200C Vds = 20V Ids = 250mA/mm Courtesy of Don Willis, Rob Dry RFMD Cascode allows distributed thermal layout vs. dual-gate Page 17 CSIC 2011 Cascode BD-Vds Robustness: Vds1/Vds2 partition • Zsource & AV1 vs. Cshunt • Vds1 & Vds2 vs. Cshunt 80 + Vds2 - 30 70 Cshunt Vds1_pp & Vds2_pp (V) Zsource (Ohms) & Av1(dB) 40 Zsource + Vds1 - Av (dB) 20 10 60 50 Vds1_pp (V) 40 Vds2_pp (V) 30 20 10 0 0.1 1 10 100 0 0.1 Cshunt (pF) 1 10 Cshunt (pF) Cshunt controls Vds_p-p voltage swing partition between devices Page 18 Stacked calculations described by UCSD papers 100 Multi-Watt GaN LNA Motivation • Low NF of GaAs PHEMTs, but with greater linearity • Enables Future Linear RF Applications • Software Defined Radios • Higher Spectral Efficient P2P • RF on Fiber • Extended CATV Page 19 8-Watt Cascode LNA MMIC 60 54.3 OIP3 (dBm) 50 750 mA 53.3 52.7 51.9 51.8 51.4 50.8 52.0 500 mA 40 30 20 0 40V-750mA S21 10 0 S11 -10 S22 -20 -30 -40 0 1 2 3 3.0 5 4 2.5 3 2.0 2 1.5 Noise Figure (dB) 20 1 0 CSIC 2011, RFIC2012 4 2.57 2.534.6 750 mA 2.20 2.19 3.8 2.08 3.73.6 3.2 3.0 3.0 2.9 2.7 2.7 3.0 2.9 1.48 2.4 2.5 2.5 1.42 2.3 500 mA 1.42 1.23 1.22 1.09 1.10 0.89 0.88 1.32 1.32 2 2.0 2.5 3 3.0 Freuency (GHz) (GHz) Frequency 3.5 1.24 1.01 0.5 0 3 2.28 1.0 Frequency (GHz) Page 20 2 Frequency (GHz) 40V-500mA- High Linearity Bias 10V-200mA - Low NF Bias 2.8325V-300mA - High Dynamic Range Bias 6 Noise Figure (dB) Gain & Return-Loss (dB) 30 1 0.0 0.5 1 1.0 1.5 1.08 4 IP3-NF Technology Comparison Multi-Watt LNA is required to achieve 55 > 45 dBm IP3 Summary of S-band LNA & Gain Block Performance [2012 RFIC] 50 OIP3 (d Bm) GaN [14] [14] [6] 45 [7] 40 HBT-NB HBT-WB HFET [3] D PHEMT [12-13] E PHEMT [10] E-PHEMT [1] 35 GaAs HBT HFET/MESFE T GaN HEMT [5] 30 D-PHEMT 25 0 1 2 NB= Narrow band tuned WB= Wide band tuned 3 4 5 Noise Figure (dB) IMS 2012 WS: WFE 6 7 8 Example: GaN Device EPI linearization for CATV [2009 BCTM Conference, Jeff Shealy, et.al.] CATV linearity is related to device Cdg (Vds) linearity. Lower Al composition results in improved GaN CATV linearity. Page 22 Page 22 IMS 2012 WS: WFE Darlington & fT-Doubler • Sidney Darlington (1953 Patent) • Increase DC current gain of a BJT • Two poles – hard to stabilize in FB • Tektronix fT-doubler , 2*fT (1980 Patent) • Two poles separated – RF feedback now feasible • Today- Millions of GaAs based RF Darlingtons are sold each year • High linearity for repeaters, driver line ups in BTS, CATV, instrumentation, Fiber • GaN has elevated performance to multi-octave, multi-watt power • Linear driver amps in a wideband amplifier line up • Linearity-BW can enable future wideband radio architectures Page 23 Sidney Darlington 1906-1997 [1] C B Q1 Q2 b b2 E Bell Labs (1953) Pat. No. 2,663,806 Darlington-pair key analog building block for several decades Page 24 APMC 2010 Tektronix Darlington Amplifier [2] Pat. No. 4,236,119 (1980) “fT Doubler” Enhancement b2 2b B Q1 2b Q2 fT 2 fT 12dB/Oct 6 dB/Oct E Less excess Phase stable FB feasible fT-doubler enables RF feedback Page 25 APMC 2010 C Darlington Cascode Amplifier – Enhanced BW RF Darlington FB Amp Darlington Cascode FB Amp Rdc Rdc OUT Cfb OUT Cfb MC MC Rfb Rfb Rfb Rfb IN MC IN M1 MC M1 M2 Rg Rg3 M3 M2 Rg Rs R1 Cbyp Rs Vg2 Vg1 Cbyp Vg1 Cbyp linearization [2006 CSIC] large signal [Krishnamurthy-UCSB] Darlington FB provides high Linearity-BW Page 26 R2 RFIC 2007 RTU4A-5 Cbyp Darlington Cascode Device Characteristics GaNGB1_DC_Vgs_vs_Ids..IDS.i (V) Ids IDS.i Darlington vs. DCAS I-V Darlington vs. DCAS Gain Conventional-Darlington Darlington-Cascode 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 Higher Knee Higher Ro 0 5 10 15 20 25 30 VDS Vds (V) GaNGB1_DC_Vgs_vs_Ids..VDS Higher Knee, lower Go Page 27 RFIC 2007 RTU4A-5 Higher Gain GaN HEMT MMIC Darlington-Cascode – P1dB > Watt 0.2um GaN HEMT MMIC fT~60GHz, BVgd ~ 60V Darlington Cascode D (IP3-P1dB) ~ 11-12 dB (3-Octaves!) LFOM= IP3/Pdc > 2.5:1 Page 28 RFIC 2007 RTU4A-5 GaN HEMT MMIC Darlington-Cascode – P1dB > Watt OIP3 Pout @ 3.5 GHz IP3 Comparison @ 15V, 400 mA Darlington-Cascode: 15V, 400 mA 46 35 OIP3 (dBm) 45 Pout & Gain (dB), PAE (%) Conventional-Darlington Darlington-Cascode 44 43 42 41 OIP3 > 41 dBm over a 4 GHz Bandwidth 40 Fo = 3.5 GHz P1dB = 30.3 dBm Psat = 31.7 dBm PAE = 21.4% 30 25 20 15 10 5 Pout(dB) Gain(dB) PAE% 0 -5 -10 0 1 2 3 4 Frequency (GHz) Improvement in IP3 Page 29 5 -30 -20 -10 0 10 Pin (dBm) Pout~1.5W, PAE~20% RFIC 2007 RTU4A-5 20 30 Summary of GaN Darlington/fT-doubler FB Amps Comparison of Broadband GaN PAs (fT-Doubler, Darlington, Darlington Cascode) Technology Design fT doubler/dualgate 0.75-um AlGaN/GaNGaAs-GaN Saphire Cascode delay-matched TWA fT doubler/singlegate 0.7-um GaN/AlGaNSaphire fT doubler/dualgate GaN-SiC fT-doubler Cascode FB Amp 0.2um T-gate GaN-SiC HEMT 0.8um GaN Page 30 Darlington Feedback DarlingtonCascode Feedback fT-doubler Construction Bandwidth Gain (dB) (GHz) 2-8 Flip-chip on ALN w/passives Flip-chip on ALN w/passives hybrid: GaN+GaAs Passive (IPC) Fully Monolithic (MMIC) Fully Monolithic (MMIC) Fully Monolithic (MMIC) 10 Vsupply Pout (W) (V) 28 5.12 fout (GHz) PAE (%) 6 21 REF [1] 1-9 11 19 1.35 8 14 0.2-7.5 11 19 >1 1-7 10 [2] 0.2-8 10 24 1.5 6 0.2-4 9-10 28 >1 1-3 15 [3] 0.2-4 10-11 28 >1 1 0.05-18.7 11 15 >1 1-4 > 20 [4] 0.05-12.3 14.5 15 >1 1-4 > 20 1.0-6.0 12.2 20 >2 1-6 24-37 *Modified from RFIC 2007 *[5] Lossy-Matched Power Amplifier Approach • Lossy match trades off Q for BW • Applied to input which is BW limited (Cgs ~ 2x Cds) • Power-BW limited by parasitic capacitance, Cds • Lumped element is thermally challenging PA Power Bandwidth Limit Gain (dB) Return Loss (dB) Wideband HPA’s covering multiple communication bands Fhigh Flow Fo QL ln() Bode-Fano Limit frequency Lumped element reactive match with lower Q more BW Page 32 Page 32 IMS 2010 WE4E-5 Schematic of Lossy Matched PA Vg Vd Bias Networks Ld RF IN Cdiv Zg Impedance Lossy match transformation Cd RF OUT Output match Apply lossy match to input which is BW-limited by Cgs Page 33 CSIC 2008 Output Match : Small signal vs. large signal match vc vc Constant out contour Pout ReZ L if Z L Z o Popt Zo Pout ReYL Z o if Z L Z o Popt Constant Pout contour RL,opt=Zo Page 34 So, minimize Im(Z L ), Im(YL ) Karthik Dissertation UCSB 2000 Comparison of broadband output networks 50 ~1.5pF 40 Drain efficiency (%) Zo ~ 50 Ohms 30 20 10 0 no compensation 0 0.5 1 F F 1.5 2 f fo L-section “best” small-signal Pi-section best large-signal pi-section compensation Page 35 Karthik Dissertation UCSB 2000 0.5 – 2.5 GHz, 10W Lossy Matched P3dB, GaN MMIC PA Drain Efficiency 43 80 P3dB (dBm) • Gain :15 – 16 dB • Pout : 9 – 13.6 W • Efficiency :45% – 64% Drain Efficiency 70 41 60 40 50 39 40 Vdq = 48V, Idq = 44mA 38 20 20 16 10 12 0 8 -10 4 -20 0 -30 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 1.0 1.5 Frequency (GHz) (Die size : 2mm x 1mm) Frequency (GHz) Page 36 2.0 S11 (dB) , S22 (dB) S21 (dB) 0.5 CSIC 2009 Session D2 30 2.5 Drain Efficiency (%) P3dB 42 Distributed Power Amps • Extends Power-BW over lossy matched approach • Absorbs output device capacitance Cds, Ropt load • Device thermal mitigation • > 4x Pd of GaAs PHEMTs • NDPA enable widest power-BW and Efficiency • Optimizes Ropt for each device section • Cascode may enable higher power-BW • Practical Limitations Page 37 Distributed Amplifier Topologies & Techniques • Convention DA [1-proceedings IRE 1936] • DC to microwave BW • Low power efficiency • Capacitive Coupled DA [2,3 - Ayasli, et.al.] • Improved Power-BW but lower gain, LF limited • Cascode DA • Thermal & Voltage Mitigation • High IP3-BW • Modest PAE though • Non-Uniform DPA [1], [4-Apel], [5-Duperrier] • Optimum Power Load for each device section • Higher power-BW and PAE • LF limited (no drain term) Page 38 Distributed Amplifier Topologies CS Distributed Amp [1] Capacitive-coupled CS Distributed Amp [2,3] Capacitive-coupled Cascode Distributed Amp Non-Uniform Distributed Power Amp [4,5] TLout2 TLout TLout9 TLout8 OUT M8_cs M2_cs M1_cs C1 ... C1 M9_cs C1 C1 ... IN TLin1 TLin2 TLin8 TLin9 Rin TLin Vg1 Cin Cin_ext Page 39 GaN HEMT vs GaAs PHEMT MMIC DA An apples-to-apples comparison Parameter Units Technology Cut-off Frequency BVdgo Circuit Type Bandwidth Gain IP3 @ 10GHz P1dB @ 10GHz Psat @ 10GHz NF @10GHz Supply Current Supply Voltage Power Density Tjunction (calculated) GHz V GHz dB dB dBm dBm dB mA V W/mm C Value 0.2um GaN HEMT 75 > 60 Cascode DA CC Cascode DA DC-24 DC-20 16.0 12.5 40.9 42.6 30.3 32.5 34.2 33.5 3.0 5.5 300 400 30 30 1.46 0.83 161 161 30V GaN 0.15um GaAs PHEMT 85 9 Cascode DA CC Cascode DA DC-22 DC-20 17.0 13.0 35.0 36.0 25.8 26.7 27.0 28.1 3.1 5.5 300 400 8 8 0.28 0.24 158 158 8V GaAs Same Tj : GaN HEMT DAs achieve 6 dB improvement in IP3 & Pout RFIC 2009 RTU1A CW Output Power as a Function of Vdd Operation CS NDPA [ IMS 2010 Reese] [ CSIC 2008 Campbell] HV FP-gate LV T-gate GaN HEMT GaAs PHEMT GaN enables higher Pout with increasing Vdd. GaN NDPA MMICs demonstrate > 10-Watts @ 10 GHz. Page 41 Modified from RFIC 2009 RTU1A Non-Uniform Distributed Power Amplifier C1 L1 Rp Rp i(t) Rp i(t) C2 Rp/2 i(t) L2 2 i(t) Rp C3 Rp/3 i(t) L3 3 i(t) C4 Rp/4 Rp i(t) LC network is tapered (Non-uniform TLINs) to present the optimum load, Rp, to each individual device. Page 42 Example: Simulated CS Load-Pull (Vdd=25V, Wg=300um) Pdel_contours_p PAE_contours_p Calculation m2m1 2 ∙ 𝑉𝑑𝑑 𝑅𝑜𝑝𝑡~ 𝐼𝑚𝑎𝑥 ∙ 𝑊𝑔 2 ∙ 25𝑉 ~ 1𝐴/𝑚𝑚 ∙ 0.3𝑚𝑚 ~167 Ω 57.15 31.25 indep(PAE_contours_p) (0.000 to 29.000) indep(Pdel_contours_p) (0.000 to 48.000) m1 indep(m1)=4 PAE_contours_p=0.772 / 8.649 level=57.052087, number=1 impedance = Z0 * (5.815 + j3.348) m2 indep(m2)=3 Pdel_contours_p=0.610 / 8.370 level=31.237924, number=1 impedance = Z0 * (3.801 + j1.074) LP Sim. Pout = 31.3dBm Page 43 Ropt (Power) ~ 205 W Example Simulated Dynamic Load Line No Cds 1.4 H 1.2 Higher frequency 1.0 0.8 0.6 0.4 0.2 0.0 -0.2 0 10 20 30 Vds (V) ts(Vds1) 40 50 GaN_CS_FET_Gmax_Cgs_Cds_NG..VDS 60 Ids (mA/mm) GaN_CS_FET_Gmax_Cgs_Cds_NG..IDS.i/0.38 ts(Ids1.i)/0.38 (H) GaN_CS_FET_Gmax_Cgs_Cds_NG..IDS.i/0.38 Ids (mA/mm) ts(Ids1.i)/0.38 (H) Effect of device Cds 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 -0.2 0 10 20 30 40 50 Vds (V) ts(Vds1) GaN_CS_FET_Gmax_Cgs_Cds_NG..VDS Ropt_LP ~ 61.5Wmm (Vds=25V) Theoretically NDPA absorbs Cds and Ropt for each section of the DA Page 44 60 Example Calculation of NDPA Optimum Ropt & TLIN Width Cascode 50V-50Ohm, 15-Watt design example FET NDPA Calculations FET Rp Opt. Power (Ohmmm) from LP 123 RL _opt (Ohm) 50 Vds (V) 50 Wg_total (mm) 2.5 Est. RF Power (W), (dBm) 15 PD (W/mm) Number, n 6 Ids (mA) (assuming Id_p/2) 600 Current Density (mA/mm) 240 PAE (%) 45 1 2 3 4 5 6 7 8 9 FET Ropt LP GaN TLIN (H=100um) Ropt_n_LP Calc. TLIN Wg (um) (Ohm) Width (um) 500 250 250 250 250 250 250 250 250 246 164 123 98 82 70 62 55 49 0.0 0.9 4.7 13.1 25.8 41.8 60.1 79.7 99.9 Cumm. Ids 120 180 240 300 360 420 480 540 600 Min M2+M1 Electromigration Min. Width 6.0 9.0 12.0 15.0 18.0 21.0 24.0 27.0 30.0 Calculations derived from CSIC 2008 Campbell, et.al. Min. width TLINs limited by practical lithography & electro-migration rules Page 45 Practical GaN TLIN Impedances - NDPA Reduce N Increases Rp_opt of the 1st section 4um 200um Practical impedances may be limited to 20-130 Ohms. This imposes a power-BW limitation (~30 Watts-10GHz?) Page 46 Summary of Recent GaN DA and NDPA Capability Summary of Recent GaN MMIC Distributed Amplifiers REF Author Circuit Topology Technology Small-Signal BW (GHz) Gain (dB) Pout (Watts) PAE (%) IP3 (dBm) Operating Voltage (V) [4] Campbell, et.al. NDPA 0.25um GaN HEMT 1.5-17 13 6-16 20-38 - 30 DC-24 15 1-2.5 - - 30 [5] Kobayashi, et.al. DC-20 12 1-3 - - 30 2-18 13 11-14 24-28 - 35 0.01-10 ~11 10 < 15 47 48 2-42 > 25 (2-stage) > 0.5 5-7 - 15 0.5-6 18.7 3.6-7 28-43 - 28 0.02-6 18 30-42 33-37 - 50 0.05-20 10 1-4 ~12 45.5 40 Cascode DA [6] [7] [8] [9] [10] Page 47 Capacitivecoupled Cascode DA 0.2um T-gate GaN HEMT IMS2010 Capacitive- 0.25um GaN Reese, et.al. coupled NDPA HEMT Hittite HMC999 datasheet Capacitivecoupled Cascode DA? ? Fraunhofer, Capacitive0.1um GaN IMS2012 coupled NDPA HEMT CREE CMPA006000 DA 2D Datasheet CREE CapacitiveCMPA006002 coupled NDPA 5D 2012 PA Symposium Capacitivecoupled DA ? 0.25um GaN HEMT Page 47 OUTLINE • Need: BW, Power, Linearity, PAE, Sensitivity, Survivability • Broadband Application • GaN Flavors (fT, Lg, BVdg, LN, Power Density) • Broadband Amplifier Topology – Trades • Cascode FB • Darlington FB • Lossy Match • DA and NDPA • Recent Results • Summary & Future Directions GaN Wideband Amplifier IP3-BW 1-4 Watt 60 Cascode FB IP3/Pdc~5.3:1 OIP3 (dBm) 55 Cascode DA 50 IP3/Pdc~1.5:1 45 40 fT-Doubler FB 35 IP3/Pdc~4.3:1 30 0 2 4 6 8 10 12 Frequency (GHz) Page 49 RFMD Recent Results 14 16 18 20 OUTLINE • Need: BW, Power, Linearity, PAE, Sensitivity, Survivability • Broadband Application • GaN Flavors (fT, Lg, BVdg, LN, Power Density) • Broadband Amplifier Topology – Trades • Cascode FB • Darlington FB • Lossy Match • DA and NDPA • Recent Results • Summary & Future Directions APMC 2010 Multi-Octave BW MMIC GaN Amplifier Topology Demonstrated Capability Metric Cascode FB Darlington FB fT-doubler Gain-BW Up to 4 GHz Up to18 GHz Up to 2.7 GHz Up to 42 GHz 8W-3GHz 2W-6GHz 5W-8GHz 13.6W-2.5GHz 30W-2.7GHz 30W-6GHz 10W-10GHz Power-BW Page 51 LossyMatch DA & NDPA NF < 1.5 dB ~3-4 dB ~3-4 dB ~3-4 dB LF limited IP3 > 51 43.5 - 45-47 LFOM = IP3/Pdc 5.3:1 2.5:1 - 4.3:1 - ~1:1 - 1.5:1 PAE up to 21% 21-37% 45-65% up to 43% Future Directions • Device Optimization • Linearize gate, EPI, Gm • E-mode • insulated gate • THz fT • higher thermal conductivity (diamond) • MMIC Design Techniques • Applying typical PA linearization to broadband topologies • Linearize the stack (Cascode) approach • System Techniques • Apply ET, PDP, etc. Page 52 Acknowledgment • RFMD – Tony Sellas, Curtis Kitani, Rainer Hillermeier, Robert Dry, Don Willis, Daniel Jin, Rama Vetury, Dave Runton, Jeff Shealy, Dave Aichele, Joe Johnson, Norm Hilgendorf • Northrop Grumman – Mike Wojtowicz, Willie O. Simmons, Don Sawdai, Schaffer Grimm, Ed Rezek, Aaron Oki, and Frank Kropschot Page 53 Thank you for your attention! Page 54 La Jolla Cove California