A 0.5 mu A offset-free current comparator for high precision current-mode signal processing

A current-domain auto-zero technique and a fully differential current amplifier are developed to realize a offset-free current comparator. Simulation results show that the current comparator can receive a 0.5 mu A input current in 1.3 mu s even if the current amplifiers and the 1-V converter have offset currents of 20 mu A. Its push-pull structure overcomes the slew-rate limiting problem and the fully differential configuration offers a high immunity to clock feedthrough noise and power supply variations.<>