A Blocker-Tolerant Receiver With VCO-Based Non-Uniform Multi-Level Time-Approximation Filter

A blocker-tolerant millimeter-wave (mm-Wave) receiver is presented using a multi-level time-approximation filter (mTAF), a voltage-controlled oscillator (VCO)-based integrator with embedded digitization, and non-uniform (NU) sampling to enhance filtering flexibility and efficiency. The mTAF approximates FIR filter responses using a digitally generated multi-level weighting pattern that controls gated integration over time. Compared with state-of-the-art reconfigurable blocker-tolerant receivers, the seven-level mTAF introduces more programmable notches, enables asymmetric filtering, and provides wider stopbands for improved blocker suppression. The VCO-based integrator simplifies circuit complexity and achieves competitive power efficiency compared with conventional Gm-C designs, while NU sampling further mitigates alias-band blockers. Fabricated in 28-nm CMOS, the prototype occupies 0.83 mm² and consumes 87 mW. The receiver achieves 65-dB maximum blocker rejection, −36-dB EVM without blockers, and −31-dB EVM with a 24-dBc blocker at 1.217-GHz offset from a 32-GHz LO.