A robust FIR filter with in situ error detection

We propose a novel FIR filter architecture that mitigates sub-critical timing violations as they occur in the pipeline structure by momentarily bypassing affected coefficients. Timing violations are detected using known in situ circuit-level techniques based on late transition detection at timing end points. The approach enables operation with a small but non-zero logical error rate, such that process, voltage and temperature margins can be eliminated without compromising stop-band attenuation. The proposed architecture is implemented in a 90nm CMOS process technology using a typical commercial standard cell implementation flow and verified using full model SPICE simulations. The filter operates at a maximum clock frequency of 420 MHz at 1 V, with an estimated area and power overhead of 26% and 24% respectively compared to a conventional implementation. At the typical process and temperature corner, the proposed architecture can be scaled in voltage down to the point of first failure at 730 mV, thereby achieving a 53% power saving, with no detectable degradation in stop-band attenuation characteristics.