The AD8613/AD8617/AD8619 are single, dual, and quad micropower, rail-to-rail input and output amplifiers that feature low supply current, low input voltage, and low current noise. The parts are fully specified to operate from 1.8 V to 5.0 V single supply, or 0.9 V and 2.5 V dual supply. The combination of low noise, very low input bias currents, and low power consumption make the AD8613/AD8617/AD8619 especially useful in portable and loop-powered instrumentation.