Op amp combining precision, high speed, and high output current drive for +or-5-V power supply operation

摘要

A monolithic operational amplifier designed for +or-5-V power supply operation is described. Precision DC performance includes 100-million V/V open-loop gain, +or-25- mu V maximum input offset voltage, +or-40-nA maximum input bias current, and 2.4-nV/ square root Hz (at 1 kHz) input voltage noise. AC performance includes 9-V/ mu s slew rate, 17-MHz bandwidth, and 1- mu s settling time to 0.1%; all are measured at unity gain. The op amp is capable of directly driving into a 50- Omega load with up to +or-80 mA of output drive current. A novel input bias current cancellation circuit achieves the low input bias current while maintaining a +or-3.5-V minimum common-mode input voltage range. A novel output short-circuit protection circuit was developed. It provides good current limiting while allowing an output voltage swing of +or-4 V. A novel input offset voltage trimming scheme using laser link cutting is introduced which consumes minimum die area while providing a +or-10- mu V trim solution (+or-3-mV trimming range) and excellent long-term stability.