A novel mixed analog/digital MAC unit implemented with SC technique suitable for fully programmable narrow-band FIR filter applications

A mixed analog/digital (MAD) multiply-accumulate (MAC) unit, implemented with switched-capacitor (SC) technique is presented. The MAC unit consist of a programmable capacitor array (PCA) for coefficient representation, and an integrator for accumulation. A coefficient compensation technique to neutralize the non-ideal MAC properties due to finite opamp gain is introduced. The MAD-MAC unit is a new concept for effective mapping of signal processing tasks on SC technique; in particular high-order fully programmable narrow-band FIR filter applications. The utilization of the MAD-MAC unit concept is shown with a simulation of a decimated 400-tap narrow-band FIR filter.