A 32dBm power amplifier for WiMAX applications in 90nm CMOS

A compact 90 nm CMOS power amplifier with integrated transformer/BALUN matching network, for 2.32.7 GHz WiMAX (802.16e) band applications, is demonstrated. The PA gain and saturated power are +18 dB and +32 dBm, respectively, working from a 3.3 V supply, with a peak power added efficiency (PAE) of 48%. A memory-less Digital Pre Distortion (DPD) technique is used to enhance the PA linearity. The measured EVM for a 64-QAM OFDM signal is improved from -24 dB to -30 dB at +25 dBm output power. Compliance with the 802.16e standard 10 MHz WiMAX mask and FCC regulations is demonstrated at +25 dBm of output power with power efficiency of ~25%, and with a measured second harmonic level of -31[dBm/MHz].