A 0.1 – 1.8 GHz, 100 W GaN HEMT Power Amplifier Module Karthik Krishnamurthy, Don Lieu, Rama Vetury, Jay Martin. Outline • Motivation • RFMD GaN Technology overview • Multi-decade band PA topologies • 25 W Unit Amplifier design and performance • 100 W Module design and performance • Thermal Evaluation • Summary Motivation • Emerging Software Defined Radio Architectures • Public Mobile Radio • Joint Tactical Radio Systems (JTRS) • Jamming Applications Handheld Manpack Smallform (HMS) / Airborne Maritime Fixed (AMF) band 30 MHz 1 10 100 Frequency (MHz) • Requirements • Multi-decade10W and higher) • High efficiency & compact size PAs (critical for handheld / mobile units) • Multi-band / multi-standard operation • Cost Savings and Inventory reduction 2000 MHz 1000 10000 GaN HEMT on SiC for HPAs Wide Bandwidth High Impedance Multi-band Operation Configurable Radios GaN-on-SiC S G GaN SiC Benefits High Efficiency D Low Capacitance Enables High Efficiency Circuit Techniques Smaller Heatsink High Power High Breakdown Voltage High Power Density High Thermal Conductivity Compact HPAs Reduced: (1) size/complexity (2) cooling (3) weight and (4) cost RFMD GaN HEMT Technology 0.5um 2.2 mm device Parameter Value Units Id-max 900 mA/mm Peak gm 250 mS/mm Vp -5 V Vbr(GD) >175 V ft 11 GHz fmax 17 GHz frequency 0.9 / 2.14 GHz 20 Peak Power 20.4 / 18.2 W 10 Peak Drain Eff 74 / 69.7 % Optimum load 31.4+j46.1 S D G • 0.5 mm Gate length • Source coupled field plate 40 GMax (dB) Gain (dB) 30 |H(2,1)| (dB) 0 -10 ft .1 1 10 Frequency (GHz) fmax [1] Class AB Bias: Ids = 44mA ; Vd = 48V 100 Broadband PA topologies Topology Resistive FBRf Zo Zo Vin Vgen Zo Vout Zo Q RLC Lossy Match Zo Zo L1 Zo Vgen C1 L2 Vout Zo Q, W Ri matching Zo network Cgs ( ) Distributed Amp Cd reverse termination L Zo RF IN Cdiv RF OUT L/2 Zo L/2 L Cin Advantages - lumped implementation - good S22 - Simple / lumped design - output optimized for Zopt - Input optimized for gain flatness - All-pass network at input implies excellent S11 - best bandwidth and gain - dissipation spread out Disadvantages - O/P not designed for Zopt - Tuning Zload affects gain flatness and S11 - Rf Pdiss / leakage issues - Rf Layout issues - Lumped circuit, so thermal design is critical - Complex circuitry - Zload optimization for each cell is complicated - poor efficiency - implementation feasibility issues 25W Unit Amplifier Specifications Specification Parameter Min. Typ. Max. Unit Recommended Operating Conditions 48 V Drain Voltage (Vdsq) Drain Bias Current 88 mA RF Input Power (Pin) 32 dBm Input Source VSWR 10:1 RF Performance Characteristics Frequency Range 50 2000 MHz Linear Gain 12 13 dB Power Gain 9 10 dB Gain flatness -1.5 1.5 dB S11 -10 dB Output Power (P3dB) 43 44 dBm Power Added Efficiency (PAE) 40 50 % [1] Test Conditions: CW Operation, Vdsq=48V, Idq=88mA, T=25ºC • Features: • • • • • • • 48V Operation Input Internally Matched to 50Ω 50–2000 MHz Instantaneous Bandwidth Gain > 16 dB over the band Output Power 25 W Power Added Efficiency > 50% Small Form Factor Copper Package Package and evalution board • 2 x 2 inch size evaluation board • AlN SO8 package 5mm x 6mm • Broadband DC Bias chokes for gate and drain • 50Ω match at the package input • Two element low pass match at the output • 50Ω feed at the input and output of the evaluation board • PCB mounted on Aluminum heat sink with fins 20 0 16 -5 12 -10 8 -15 -20 0 0.0 0.5 1.0 1.5 • Frequency : 1000 MHz • Gain : 12 dB • P3dB : 28.2 W • PAE : 49 % -25 2.0 45 • Bandwidth: 50 – 2000 MHz • Gain: 12 dB • Input return loss: < 9 dB Output Power (dBm) Frequency (GHz) 60 Output Power PAE Gain 40 35 50 40 30 30 25 20 20 10 15 0 5 10 15 20 Pin (dBm ) 25 30 35 PAE (%), Gain (dB) S21 S11 S22 4 • Vdq = 48V, Idq = 88mA S11 (dB), S22 (dB) S21 (dB) Unit Amplifier Performance 46 80 45 70 44 60 43 50 P2dB 42 40 PAE 41 0.0 0.5 PAE (%) P2dB (dBm) Unit Amplifier Performance 30 1.0 1.5 2.0 Frequency (GHz) • Vdq = 48V, Idq = 88mA 15 • Bandwidth: 50 – 2000 MHz • Gain over band: 11 – 12 dB • Output power: 23.6 – 30.9 W • PAE: 39.4 – 57.0% Gain (dB) 12 9 6 0.25 W 2.5 W 25 W 3 0 0.0 0.5 1.0 Frequency (GHz) 1.5 2.0 PA Module Topology Vg • Pairs of devices combined through 25Ω traces and further combined together using the balun. Vd • Ferrite loaded broadband 1:1 Balun at input and output. RF IN 25 25 • 50Ω coax with 0.2dB/m loss, RF that can handle 162 W at 1 GHz OUT 25 25 • Dual aperture core high frequency ferrite from Fair-Rite corp minimizes board space and provides broad bandwidth • Gate bias feeds isolated through a 470Ω resistor, and jumpered together. Vd • 82nH high-Q bias inductors at drain of each device, and the bias feed jumpered together. • 115Ω ferrite (at 100 MHz) at the drain bias feed to extend low frequency performance. PA Module • 2 x 2 inch size • Dual aperture core high frequency ferrite from Fair-Rite corp minimizes board space and provides broad bandwidth • 50Ω feed at the input and output of the PA module • Gate and Drain bias feeds for individual devices jumpered together • PCB soldered down to a copper block, and mounted on Aluminum heat sink with fins Balun performance 0 S21 S21 (dB) -0.2 -5 S11 S22 -0.4 -10 -0.6 -15 -0.8 -20 -1.0 -25 -1.2 -30 0.0 0.5 1.0 1.5 Frequency (GHz) 2.0 • Insertion loss (back to back) : 0.5 – 0.9 dB • Insertion loss per balun : 0.45 dB • Return loss: 18 – 28 dB S11 (dB), S22 (dB) 0.0 5 12 0 9 -5 6 -10 3 -15 0 -20 S21 (dB) 15 0.0 0.5 1.0 1.5 S11 (dB) , S22 (dB) 100 W Module Small Signal performance 2.0 Frequency (GHz) • Bandwidth: 50 – 1800 MHz • Gain: 11 dB • Input return loss: 9 dB • Vdq = 50V, Idq = 360mA 100 W Module CW performance 53 15 PAE Pout (dBm) 9 6 Pin = 20 dBm 3 70 51 60 50 50 49 40 48 30 PAE (%) 52 12 Pin = 40 dBm 0 0.0 0.4 0.8 1.2 1.6 2.0 0.0 0.4 0.8 1.2 1.6 2.0 Frequency (GHz) Frequency (GHz) 55 • Bandwidth: 100 – 1800 MHz • Gain over band: 11 – 13.2 dB • Output power: 94 – 142 W • Efficiency: 40.6 – 74 % Output Power (dBm) Gain (dB) 80 Pout 200 MHz 800 MHz 1200 MHz 1600 MHz 50 45 40 35 30 15 20 25 30 Pin (dBm ) 35 40 45 15 • Vdq = 50V, Idq = 360mA 12 • Frequency : 200 MHz • Pout : 128.4 W 9 • PAE : 68.0 % 6 200 MHz 800 MHz 1200 MHz 1600 MHz 3 • Drain efficiency : 74 % 0 30 35 40 45 50 70 55 Pout (dBm ) 200 MHz 800 MHz 1200 MHz 1600 MHz 60 50 • Frequency : 1600 MHz • Pout : 125.4 W • PAE : 61.8 % • Drain efficiency : 67.3 % PAE (%) Gain (dB) 100 W Module CW performance 40 30 20 10 0 30 35 40 45 Pout (dBm ) 50 55 Two Tone Linearity Performance • Vdq = 50V IMD3 vs. Pout (2‐Tone 1MHz Seperation, Vd = 50V, Idq varied, fc = 1600MHz) • Idq = Varied 180mA 360mA 540mA 720mA 900mA ‐15 ‐20 ‐25 • Fc = 1600 MHz • Tone spacing = 1MHz Gain vs. Pout ‐30 (2‐Tone 1MHz Seperation, Vd = 50V, Idq varied, fc = 1600MHz) 16 ‐35 15 ‐40 14 13 ‐45 ‐50 0.1 1 10 100 Pout, Output Power (W‐PEP) 1000 Gain (dB) IMD3, Intermodulation Distortion (dBc) ‐10 12 11 180mA 360mA 540mA 10 9 720mA 900mA 8 • Optimum Idq = 720 mA 7 6 0.1 1 10 Pout, Output Power (W‐PEP) 100 1000 Two Tone Linearity Performance IMD vs. Output Power (Vd = 50V, Idq = 720mA, f1 = 1599.5MHz, f2 = 1600.5MHz) 0 IMD3 ‐IMD5 IMD5 ‐IMD7 IMD7 ‐20 ‐30 Drain Efficiency vs. Pout (2‐Tone 1MHz Seperation, Vd = 50V, Idq varied, fc = 1600MHz) 60 ‐40 ‐50 50 ‐60 ‐70 0.1 1 10 100 Pout, Output Power (W‐ PEP) • Frequency : 1600 MHz • Pout : 65 W • IMD3 < 35 dBc • Drain efficiency : 41 % 1000 Drain Efficiency (%) Intermodulation Distortion (IMD ‐ dBc) ‐10 ‐IMD3 40 30 180mA 360mA 540mA 20 720mA 900mA 10 0 0.1 1 10 Pout, Output Power (W‐PEP) 100 1000 Infrared thermal measurements • Vdq = 48V, Idq = 88mA • Base plate temperature : 85ºC Peak Junction Temperature vs Power Dissipation Peak Junction Temperature(oC) 300 250 200 150 100 50 Leaded Cu Package 0 0 5 10 15 20 Power Dissipation (W) • Junction temperature of 209.3ºC 25 30 35 Summary • We’ve demonstrated a 100W, 0.1 – 1.8 GHz, 50V GaN HEMT PA module with >40% drain efficiency over the band Output power (W) Bandwidth (GHz) 94 – 142 0.1 – 1.8 Gain (dB) Supply Drain Voltage (V) Efficiency (%) 11 – 13.2 50 41 – 74 • Further work is in process: • Extending the bandwidth to 50 MHz – 2.5 GHz • Improving efficiency and thermal performance • Broadband / High efficiency / compact size serve applications including PMR (Public Mobile Radio) and test instrumentation. 20 Do You Have Any Questions? 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