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 under 1.2 V/C, guaranteed over the full military temperature range. Open-loop gain of the OP400 is over 5,000,000 into a 10 k load, input bias current is under 3 nA, CMR is above 120 dB, and PSRR is below 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 industry-standard quad pinout which does not have null terminals.