DC-DC converter for WLAN power amplifier

A buck converter to control the supply voltage and a Power Amplifier (PA) for the Wireless Local Area Network (WLAN) application are presented in this paper. By using the buck converter the efficiency improvement in low power mode of the PA can be achieved. The buck converter is implemented in TSMC 0.35 μm CMOS process. The maximum efficiency of 98% is shown at 3.4 V of the output voltage of the buck converter, and the efficiency of 90% is achieved for 2 V with the load resistance of 12 Ω. The maximum ripple across the overall output voltage range is less than 12 mV. The WLAN PA is implemented in WIN 2 μm InGaP HBT process. The maximum linear output power of 22 dBm is obtained for the Error Vector Magnitude (EVM) of 4% with 64QAM OFDM signal at 2.5 GHz. The Power Added Efficiency (PAE) is 20% at 22 dBm.