An 8-Watt 250-3000 MHz Low Noise GaN Feedback Amplifier MMIC with > +50 dBm OIP3 Kevin W. W Kobayashi RFMD, Torrance CA OUTLINE • • • • • Motivation 0.25um Commercial GaN MMIC Design Results Summary Motivation • Future GaN trends – Power Density Æ Wideband Linearity – Higher frequency, lower voltage – E-D E D for mixed signal MMICs • GaN Linear Applications – Software S ft Defined D fi d Radios R di (SDR) – Phased Array – BTS – CATV C /Fiber (FTTX) • Æ Common Need: > octave-BW, high-linearity, LNAs, PAs, SWs • This work – Demonstrates a new linearity benchmark for GaN MMIC LNAs OUTLINE • • • • • Motivation 0.25um Commercial GaN MMIC Design Results Summary Microwave--mmW GaN HEMT Technology Microwave 0.25um GaN HEMT Foundry Technology Parameter Units Northrop Grumman Application Frequency GHz up to 40 Gate Structure - T-gate Imax mA/mm 1000 Gm mS/mm 325 Vbd V 80 Operating Vds V up to 28V fT GHz 47 @ 25V Power Density W/mm ~2 @ 40G Backside Vias - Yes Microwave--mmW GaN HEMT Technology Microwave Plated Top Metal Airbridge Inductor SiN Passivation HEMT TFR 4 mil SiC Substrate VIA • • • • • • • • 0.25um T-gate HEMT devices 150pF/mm2 MIM capacitors 2 metal layers Airbridges NiCr Thin Film Resistor Substrate Vias Silicon Carbide substrate Operation up to Vds = 28V Pulsed Drain Current (A/mm) Features 1.4 1.2 1 0.8 0.6 0.4 0.2 0 0 20 40 Drain-Source Voltage (V) 60 State-ofStateof-thethe-Art GaN MMIC Noise Figure 4 [This Work] Cascode LNA 8-Watt Noise e Figure ((dB) 35 3.5 3 [11] [1] HRL 25 2.5 < 1 Watt Dual-gate LNA [3] NG 2 [4] NG [2] UCSB 15 1.5 [9] NG 1 [10] [5]NG [6] SIRENZA-NG CS-LNA 2 Watt 2-Watt 0.5 [7] RFMD-NG, T= -10C 0 0 2 4 F Frequency (GHz) (GH ) 6 8 OUTLINE • • • • • Motivation 0.25um Commercial GaN MMIC Design Results Summary Common-Source vs. Cascode Performance Common‐source Cascode/*Dual gate Practical Vdd 20V ((T‐gate) g ) 40V Pout , IP3 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 St bilit Stability poorer Thermal Analysis 4 fingers x 125um (Wg = 500um Unit cell) 250 Tjuncttion (C) 225 200 198 205 205 198 175 150 Tbase = 85C 125 100 75 Courtesy of Don Willis, Rob Dry 1 2 3 Finger # 4 DC I-V Comparison A/mm 12 1.2 IDS (A/mm) 1.0 COMMON-SOURCE CASCODE 0.8 0.6 0.4 0.2 50 ohm 0.0 0 10 20 30 40 VDS 50 60 70 80 MAG Comparison Wg = 500um HEMT Ma ax Gain (d dB) 50 40 CASCODE 30 20 10 COMMON-SOURCE 0 0 10 20 30 40 50 60 70 80 90 100 Frequency (GHz) GaN Cascode Feedback Design GaN Cascode Feedback LNA • Cascode -Thermal Thermal -Electrical • Wg_total = 3 mm • Vdd = 40V • Idd = 500-750mA 500 750mA Chip size is 1.6x1.3 mm2 4 finger x 125um (Wg=500um unit cell) OUTLINE • • • • • Motivation 0.25um Commercial GaN MMIC Design Results Summary Wide--band S Wide S--parameters Performance 40V--750mA 40V 750 A D Design ig 40V-750mA Gain & Retturn-Loss s (dB) 30 20 S21 10 0 S11 -10 10 S22 -20 -30 30 -40 0 1 2 Frequency (GHz) 3 Noise Figure 40V--500mA 40V 500 A & 750mA 750 A D Designs ig Noise e Figure (dB) 6 5 4 3 3.0 2.9 2.7 2.4 2 2.7 2.3 3.0 2.5 4.6 750 mA 3 8 3.73.6 3.8 3.2 3.0 2.9 2.5 500 mA 1 0 0 1 2 Frequency q y ((GHz)) 3 4 Noise Contribution Calculation Tj = 150C Noisse Figure (dB) 6 5 MEASURED 4 3 CALCULATED 2 Channel Thermal Noise 4ΚΤ Γ(1/gm) Γ(1/ ) II_gate t shot h t noise? i ? CALCULATED 1 FB Resistor R Ri R Rg+Ri+Rs 0 0 1 2 Frequency (GHz) 3 4 Fukui Equation Output IP3 40V--750 mA 40V A & 500 500mA AD Designs ig 60 54.3 OIP P3 (dBm)) 50 750 mA 52.7 53.3 51.9 51.8 51.4 50.8 52.0 500 mA 40 30 20 0 1 2 Frequency (GHz) 3 4 Output IP3 as a function f ti off Vdd 60 OIIP3 (dBm m) 50 40 30 20V 30V 40V 20 10 Δ IP3 = 6dB 0 0 1 2 3 Frequency (GHz) Frequency (GHz) 4 P1dB & Psat Psa at & P1dB B (dBm) 45 750 mA 41.37 40.03 39.2 40 35 39.2 37.7 500 mA 30 Δ (Psat (Psat-P1dB) P1dB) ~ < 1 dB 25 20 0 1 2 Frequency (GHz) 3 IP3-NF IP3T h l g C Technology Comparison i Summary of S-band LNA & Gain Block Performance 55 GaN [6] OIP3 3 (d Bm) HBT-WB HBT-NB [This Work] 50 HFET 45 [3] [7] 40 [12-13] [10] E-PHEMT 35 D PHEMT E PHEMT [1] GaAs HBT [5] HFET/MESFET 30 D PHEMT D-PHEMT GaN HEMT 25 0 1 2 NB= N NB Narrow b band d ttuned d WB= Wide band tuned 3 4 5 Noise Figure (dB) 6 7 8 GaN MMIC Topology Comparison ( (reported t d NF & IP3) Summary of GaN MMIC FB LNA Performance (S-, C-band) Reference Topology [1] Matched-FB [3], [5] [6] [7] [6], High NF Best BW Dual-gate FB Noise OIP3 Figure (dB) (dBm) 2.4 37.8* 1.5 43 1.03 32 Darlington [11] [13] [11], DA This Work Cascode FB 9.5:1 44-46 30 < 25 dBm 32.9 6.64:1 11-13 42-44 32.8 4.2:1 11.2 4.3** 43.5 31 3.7 12.5 3.3 29 22 4.3** 42-44 30-33 ~2:1 11-12 2.5 48.4 36.8 3.5:1 11.7 3 51.9 38.5 5.2:1 13.4 Source-Match- 0.75-0.9 FB 0.25-0.45 [12] P1dB LFOM Δ (IP3-P1dB) (dBm) (IP3/Pdc) 13 2.0:1 7 Lowest NF Summary • Benchmark- 0.25um T-gate GaN MMIC 8-Watt LNA – Cascode – Wideband NF ~2.5-3dB ~2 5 3dB – High IP3 > 51 dBm • Respectable Linearity FOMs – IP3/Pdc LFOM ~ 5.2:1 – (IP3-P1dB) ~11.7-13.4dB – Improves with device maturity • Future work – E-mode GaN,, MISFET – mmW applications up to 40 GHz ACKNOWLEGMENT • RFMD – Tony Sellas, Curtis Kitani, Robert Dry, Don Willis, Daniel Jin, Joe Johnson, Dave Aichele, Jeff Shealy, Karthik Krishnamurthy, Ramakrishna Vetury, Conrad Young, Alastair Upton, Brad Nelson, Dave Runton, Jay Martin, Norm Hilgendorf • Northrop Grumman – Richard To, Wen-Ben Luo, Ioulia Smorchkova, Benjamin Heying, William Sutton YaoChung Chen Sutton, Chen, Mike Wojtowicz Wojtowicz, Aaron Oki, Schaffer Grimm, Ed Rezek, and Frank Kropschot