A Reconfigurable Analog FIR Filter Achieving -70dB Rejection with Sharp Transition for Narrowband Receivers.

We present a compact, highly reconfigurable charge-domain analog-FIR (AFIR) filter for high channel selectivity receivers such as BLE, Zigbee, and IoT applications. This architecture demonstrates excellent power-scaling with reconfigurability to different bandwidth and desired stopband rejection. The charge-domain FIR filter modulates both pulse width and transconductance which multiply to generate the charges of the FIR coefficient. Varying both time and transconductance achieves high programmability enabling a wide range of bit-resolution and FIR tap number combinations to achieve a customizable filter response at optimal power. Fabricated in 28nm CMOS, the filter achieves −70dB stopband rejection with a sharp transition and a low power consumption of 0.356mW.