APPLICATION NOTE CGH55030-TB 30W BWA Reference Amplifier Introduction The CGH55030-TB is a linear amplifier circuit for the 5.5 – 5.8 GHz BWA market using a Cree CGH35030F GaN HEMT transistor as a means of demonstrating the improved performance characteristics that are possible in comparison with existing technologies. The prototypes were evaluated under 802.162004 WiMAX protocol. This application note describes the typical performance that has been achieved and that which can be expected when evaluating the demonstrators. Details of the circuit are included for further understanding of the topology and all necessary information has been provided to aid in -005 ote: APPNOTE Application N Rev. A reproduction of the amplifier. Features • 300 MHz Instantaneous Bandwidth • 10 dB Small Signal Gain • 25 % Efficiency at 5 W Average Power • WiMAX Fixed Access 802.16-2004 OFDM • DOCSIS 16-QAM Subject to change without notice. www.cree.com Basic Amplifier Specification Maximum Ratings for Evaluation of Demonstrator at 25°C Minimum Maximum Units Drain-Source Voltage Parameter 20 35 Volts Gate-to-Source Voltage -10 +2 Volts Frequency Notes 5.5 5.8 GHz Input Power Level - 30 dBm Peak Signal Gain Compression - 3 dB May reduce maximum input power if PAR > 10 dB VSWR - 5:1 dB Limit for stability testing Operating Junction Temperature - 175 ˚C Thermal Resistance1 - 2.5 ˚C/W -10 +100 ˚C Case Temperature Average Power with PAR < 10 dB Note: 1 Thermal resistance is estimated based on using the CGH35030 transistor 2 CW Testing is not recommended for the demonstrator - carrier should be digitally modulated. Summary of Typical Demonstrator Performance Characteristics Frequency Units 5.50 GHz 5.65 GHz 5.80 GHz Small Signal Gain 9.5 10.0 9.5 dB Power Gain 8.0 9.0 8.5 dB Input Return Loss -10.8 -22.0 -9.3 dB EVM at POUT = 5 W 2.4 1.5 2.0 % RCE at POUT = 5 W -32.5 -36.3 -34.0 dB Drain Efficiency at POUT = 5 W 26 28 28 % PAE at POUT = 5 W 22 24 24 % Note: 1 Under 802.16-2004 OFDM, 3.5 MHz Channel BW, 1/4 Cyclic Prefix, 64 QAM Modulated Burst, 5 ms Burst, Symbol Length of 59, Coding Type RS-CC, Coding Rate Type 2/3. 2 Individual device characteristics are as per CGH35030 data sheet 3 Performance data taken at VDD = 28 V, IDQ = 250 mA Copyright © 2008 Cree, Inc. All rights reserved. Permission is given to reproduce this document provided the entire document (including this copyright notice) is duplicated. The information in this document is subject to change without notice. Cree and the Cree logo are registered trademarks of Cree, Inc. Other trademarks, product and company names are the property of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association. Cree Confidential and Supplied under terms of the Mutual NDA. APPNOTE-005 Rev. A Cree, Inc. 4600 Silicon Drive Durham, NC 27703 USA Tel: +1.919.313.5300 Fax: +1.919.869.2733 www.cree.com/wireless Typical Performance of the CGH55030-TB BWA Demonstrator 12 5 S21 0 S11 8 -5 6 -10 4 -15 2 -20 0 S11 (dB) S21 (dB) 10 -25 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 6.0 6.1 Frequency (GHz) Figure 1 -Small Signal Gain vs Frequency 4.0 3.5 5.50 GHz 5.65 GHz 5.80 GHz 3.0 EVM (%) 2.5 2.0 1.5 1.0 0.5 0.0 15 20 25 30 35 40 Power Out (dBm) Figure 2 -WiMAX EVM vs. Average Output Power at 5.50, 5.65, and 5.80 GHz Copyright © 2008 Cree, Inc. All rights reserved. Permission is given to reproduce this document provided the entire document (including this copyright notice) is duplicated. The information in this document is subject to change without notice. Cree and the Cree logo are registered trademarks of Cree, Inc. Other trademarks, product and company names are the property of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association. Cree Confidential and Supplied under terms of the Mutual NDA. APPNOTE-005 Rev. A Cree, Inc. 4600 Silicon Drive Durham, NC 27703 USA Tel: +1.919.313.5300 Fax: +1.919.869.2733 www.cree.com/wireless Typical Performance of the CGH55030-TB BWA Demonstrator 35 30 Drain Efficiency (%) 25 5.50 GHz 20 5.65 GHz 5.80 GHz 15 10 5 0 15 20 25 30 35 40 Power Out (dBm) Figure 3 -CGH55030-TB Drain Efficiency vs. Average Output Power at 5.50, 5.65, and 5.80 GHz 3.0 30 30 W Drain Efficiency 2.5 29 2.0 28 1.5 27 1.0 26 0.5 25 0.0 5.45 5.50 5.55 5.60 5.65 5.70 5.75 5.80 Drain Efficiency (%) EVM (%) 30 W EVM 24 5.85 Frequency (GHz) Figure 4 -CGH55030-TB WiMAX EVM & Efficiency at POUT = 5 W Average vs. Frequency Copyright © 2008 Cree, Inc. All rights reserved. Permission is given to reproduce this document provided the entire document (including this copyright notice) is duplicated. The information in this document is subject to change without notice. Cree and the Cree logo are registered trademarks of Cree, Inc. Other trademarks, product and company names are the property of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association. Cree Confidential and Supplied under terms of the Mutual NDA. APPNOTE-005 Rev. A Cree, Inc. 4600 Silicon Drive Durham, NC 27703 USA Tel: +1.919.313.5300 Fax: +1.919.869.2733 www.cree.com/wireless Details of the CGH55030-TB BWA Demonstrator Circuit CGH55030-TB 3-000561 REV2 PRELIMINARY Figure 5 -CGH55030-TB WiMAX Demonstrator Printed Circuit Board Assembly CGH55030-TB BWA Demonstrator Bill of Materials Reference Designator Description CAP, 1.2 PF±0.10 pF, 0603, ATC 600S 1 R1 RES, 1/16W, 0603, 1%, 562 OHMS 1 C2 CAP, 0.3 PF±0.05 pF, 0402, ATC 600L 1 R2 RES, 1/16W, 0603, 1%, 22 OHMS 1 C9 CAP, 0.4 PF±0.05 pF, 0603, ATC 600S 1 C4, C11 CAP, 10 PF±5%, 0603, ATC 600S 2 C5, C12 CAP, 39 PF±5%, 0603, ATC 600S 2 C6, C13 CAP, 200 PF±5%, 0603, Murata GRM1885C2A201JA01D 2 C7, C14 CAP 330000PF 100V X7R, 0805,Murata GRM21BR71E334KA01L 2 CAP, 10 UF 16V SMT TANTALUM 1 C15 CAP 1.0 UF 100V 10% X7R, 1210, Murata GRM32ER72A105KA01L 1 C16 CAP 33 UF 100V ELECT FK SMD Panasonic PN: EEV-FK2A330P 1 SMA Connector 2 HEADER RT> PLZ .1 CEN LK 5 POS 1 3-00561 Rogers RO4350 0.020” THK with 1oz Cu plated to 2oz PCB is sweat soldered onto an aluminum plate of 0.25” 1 CGH35030F 1 C8 J3, J4 J1 PCB Transistor Copyright © 2008 Cree, Inc. All rights reserved. Permission is given to reproduce this document provided the entire document (including this copyright notice) is duplicated. The information in this document is subject to change without notice. Cree and the Cree logo are registered trademarks of Cree, Inc. Other trademarks, product and company names are the property of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association. Cree Confidential and Supplied under terms of the Mutual NDA. Quantity C1 APPNOTE-005 Rev. A Cree, Inc. 4600 Silicon Drive Durham, NC 27703 USA Tel: +1.919.313.5300 Fax: +1.919.869.2733 www.cree.com/wireless Details of the CGH55030-TB BWA Demonstrator Circuit, continued Figure 6 -Schematic of CGH55030-TB WiMAX Demonstrator Circuit Conclusion This application note has shown the performance advantages of using discrete GaN HEMT transistors for amplifiers in the 5.5-5.8GHz band for BWA systems. The reference design here shows that it is possible to acheive efficiency 5 times higher than existing solutions1,2, whilst maintaining useful gain and excellent linearity at high average power levels. Such amplifiers are also capable of providing this performance over an instantaneous bandwidth of 300MHz with very little tuning. This reference design was generated with first pass success using Cree’s large signal models, which are available on request. Reference [1] Triquint (2008) Broadband / BWA WiMAX Products http://www.triquint.com/prodserv/markets/broadband/bwa_wimax.cfm [2] Toshiba America Electronic Components, Inc. (2008) C-Band Power GaAs IMFETs. http://www.toshiba.com/taec/catalog/line.do?familyid=18&lineid=7039 Copyright © 2008 Cree, Inc. All rights reserved. Permission is given to reproduce this document provided the entire document (including this copyright notice) is duplicated. The information in this document is subject to change without notice. Cree and the Cree logo are registered trademarks of Cree, Inc. Other trademarks, product and company names are the property of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association. Cree Confidential and Supplied under terms of the Mutual NDA. APPNOTE-005 Rev. A Cree, Inc. 4600 Silicon Drive Durham, NC 27703 USA Tel: +1.919.313.5300 Fax: +1.919.869.2733 www.cree.com/wireless CGH55030-TB BWA Demonstrator Setup Instructions 1. Position the demonstration amplifier fixture such that the RF source (50 Ω) is connected to the left side of the fixture and the RF load (50 Ω) is connected to right side of the fixture. 2. Connect the 5-pin bias cable. 3. Verify all power supplies are at 0 volts before turning on. 4. Connect the RED wires to the drain power supply. 5. Connect the WHITE wire to the gate power supply. 6. Connect the BLACK wires to the return (common) terminals of the gate and drain power supplies. 7. Verify connections with the schematic shown in Figure 6. 8. Adjust the power supply to –5.0 V. Turn on the gate bias power supply. 9. Adjust the power supply to +28 Volts. Turn on the drain bias power supply. There should be NO current flow from the power supply. 10. Adjust the gate bias supply until a drain current (IDQ) of 250mA is measured. 11. Apply low RF drive, 10dBm (5.65 GHz), and verify the amplifier has approximately 10dB of gain. Increase RF drive to the desired output level and verify the performance with the data shown in this application note. Copyright © 2008 Cree, Inc. All rights reserved. Permission is given to reproduce this document provided the entire document (including this copyright notice) is duplicated. The information in this document is subject to change without notice. Cree and the Cree logo are registered trademarks of Cree, Inc. Other trademarks, product and company names are the property of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association. Cree Confidential and Supplied under terms of the Mutual NDA. APPNOTE-005 Rev. A Cree, Inc. 4600 Silicon Drive Durham, NC 27703 USA Tel: +1.919.313.5300 Fax: +1.919.869.2733 www.cree.com/wireless