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Politecnico di Bari Engineering Faculty - Electronics Engineering Course Thesis in MICROWAVES.
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Politecnico di BariEngineering Faculty - Electronics Engineering CourseThesis in MICROWAVES In partnership withSTMicroelectronicsDESIGN OF A CLASS 1 POWER AMPLIFIER FOR BLUETOOTHTM APPLICATIONSAdvisors CandidateProf. Antonella D’Orazio Giovanni DE FILIPPOTutor.Dr. Roberto Antonicelli.A.Y. 2004-05
OUTLINE • CHECK OF SUITABLE COMPONENTS • DESIGN AND ANALYSIS USING ANSOFT DESIGNER SV • REALIZATION • MEASUREMENTS • STLC2500 WITH CLASS 1 PA IMPLEMENTATION
DESIGN CHALLENGES • LOW COST • HIGH POWER GAIN • MINIMAL BOM
ELECTRICAL SPECIFICATIONS • Central Frequency: 2.45 GHz • Bandwidth: 100 MHz • Input and Output Impedance: 50 Ohms • Output Powers: 10, 14 and 18 dBm • Supply Voltage: 2.75 Volts • Operating Temperature: -40 to +85°C
Enable and Power Control Biasing Transistor RF Choke to DC Bias Input Matching DC Block Output Matching DC Block DESIGN MODEL
Output Matching DC Block Input Matching DC Block Trasmission Line Model RF Power Transistor RF Choke to DC Bias DESIGN MODEL
ANALYSIS Gain from 500 MHz to 3 GHz S11 and S22 at 2.45 GHz
ANALYSIS Stability factor from 500 MHz to 3 GHz Input and output return loss from 500 MHz to 3 GHz
REALIZATION Photograph of the Class 1 PA PCB Layout
MEASUREMENTS Photograph of the Test Setup Class 1 Power Amplifier and Measurement Setup
MEASUREMENTS S22 in Bluetooth Band S11 in Bluetooth Band
MEASUREMENTS Gain, Output Power and Efficiency versus Input Power at 27 °C
MEASUREMENTS Output Power Efficiency versus Input Power for different Temperatures
MEASUREMENTS Pout and Efficiency vs Pin at various Temperatures and Vcc Vcc = 2.50 V Vcc = 3.00 V
PERFORMANCE OVERVIEW • Compression Point P-1dB = 20 dBm • Power Gain Gp = 12 dB • Current consumption at max power Icc = 53 mA • Added Efficiency η = 70 %
STLC2500 CLASS 1 SOLUTION Output Power Output Spectrum, Adjacent Channel Power
STLC2500 CLASS 1 SOLUTION RF = LO – BB = 2.44084 GHz IM = LO + BB = 2.44116 GHz PULLING = LO – 3BB = 2.44052 GHz Pulling Behavior at Default Gain Settings Output Spectrum
CONCLUSIONS • Single transistor, small sized Bluetooth Class 1 power amplifier • Lowest cost in marketplace • High gain and high 1 dB-compression point • 12mA of quiescent current and 70% total efficiency • Single 2.75V supply voltage • Minimum BOM • Stable behavior versus temperature and Vcc