A single-chip (67x90 mil) integrated-circuit operational amplifier using thin-film resistors and super-gain transistors has been designed to achieve dc follower accuracies of 0. 001 percent with 100-k OMEGA source resistance. The circuit achieves gains of 140 db using thermally balanced layout designs for both input and output stages, nulled drifts of 0. 3 mu v/ degree C, and offset currents well under 1 nanoamp. All other dc specifications including power-supply variation error (PSRR), common-mode gain error (CMRR), etc. , are in the 1-10 ppm error range. A procedure is given by which long-term drifts of less than 10 mu v/month can be assured.
