A WCDMA/WLAN digital polar transmitter with AM replica feedback linearization in 65nm CMOS

A 65nm CMOS digital polar transmitter for WCDMA and WLAN is presented, which consists of a 9bit digitally-controlled switch-capacitor polar modulator and a 6-bit power amplifier array with a proposed linearity-enhancement technique. Even without AM-AM pre-distortion, the transmitter system measures RMS-EVM of 2.83% and 4.07% for WCDMA and WLAN 54-Mb/s OFDM, respectively; while providing a peak output power of 20.4dBm with PAE 32.3%.