A RAIL-TO-RAIL PING-PONG OP-AMP

A rail-to-rail ping-pong op-amp achieves offset cancellation and 1/f n oise reduction without folding of the input spectrum, The clocking sch eme minimizes the clock feedthrough and the residual offset due to cha rge injection, With a clock frequency of 100 KHz, the residual offset is less than 100 mu V, and the input referred noise is about 225 nV/Hz (1/2). The rail-to-rail distortion at 1 kHz is lower than -71 dB, The total silicon area is 610 x 420 mu m(2), and tile circuit dissipates 1 .5 mW from a single 5 V supply.