Radio receiver front-end using time-based all-digital ADC (TAD)

A direct-conversion RF-receiver IC implemented in 65nm CMOS, which has an RF front-end and all-digital differential time-based analog-to-digital converter (TAD) with 4-time-interleave technique for high resolution, is presented. The RF front-end contains passive mixers using wideband gm-cells and switches. When OFDM 16QAM RF signal (input power: −45.4dBm, BW: 20MHz) of 500M, 1.5G, and 2.5GHz is demodulated, EVM is −27.8, −27.4, and −17.3dB, respectively.