The OP400 is the first monolithic quad operational amplifier that features OP77-type performance. Precision performance is not sacrificed with the OP400 to obtain the space and cost savings offered by quad amplifiers. The OP400 features an extremely low input offset voltage of less than 150 V with a drift of less than 1.2 V/C, guaranteed over the full military temperature range. Open-loop gain of the OP400 is more than 5 million into a 10 k load, input bias current is less than 3 nA, CMR is more than 120 dB, and PSRR is less than 1.8 V/V. On-chip Zener zap trimming is used to achieve the low input offset voltage of the OP400 and eliminates the need for offset nulling. The OP400 conforms to the industrystandard quad pinout, which does not have null terminals.