A Blocker-Tolerant Non-Uniform Sub-Sampling Receiver With a Non-Uniform Discrete-Time FIR Filter

Abstract

A non-uniform (NU) sub-sampling receiver (RX) with a NU discrete-time FIR (NU DT FIR) filter can create multiple tunable frequency notches both near and far from the passband via predesigned NU sampling clocks and filter coefficients. NU DT finite impulse response (FIR) acts as an anti-aliasing (AA) filter for a nonuniformly sampled signal which relaxes the subsequent ADC speed and dynamic range (DR). To save power and area and to improve linearity, the FIR filter is implemented in the current domain and shares the capacitive DAC with a subsequent asynchronous SAR ADC. A proof-of-concept NU DT FIR RX is implemented in 28 nm CMOS. It achieves up to 42 dB of blocker rejection with B1dB of 4 dBm. The receiver measures −27.4 dB EVM for a 64-QAM 100 MSymbol/s signal centered at 20 GHz in the presence of a 10-dBc blocker. The end-to-end RX consumes 24 mW from a 1-V supply and occupies an active area of 0.072 mm2.