Precision zero-drift op-amp for DC-accurate signal chains
The key differentiator is the 1 µV maximum input offset voltage — this is the spec that defines the part: it eliminates the need for system-level offset calibration in precision weigh scales, thermocouple interfaces, and current-sense amplifiers. Supply current draws 100 µA, making it suitable for loop-powered or battery-operated transmitters. The output stage is rail-to-rail, but the input common-mode range does not extend to the positive rail — a typical fit constraint for single-supply designs below 5 V.
An input offset voltage of 1 µV max lets the designer skip the trim potentiometer and the calibration step in production. For a bridge sensor or shunt-based current monitor, that offset translates directly into a DC error at the output amplified by the closed-loop gain. At a gain of 100, 1 µV of input offset becomes 100 µV of output error — negligible in most 12-bit systems. The 150°C rating covers under-hood automotive, downhole instrumentation, and industrial engine-bay environments, though note the part carries no AEC-Q100 grade — the temperature spec alone is not a qualification.
550 kHz GBW and 100 µA supply — design budget trade-off
The 550 kHz gain-bandwidth product sets the usable closed-loop bandwidth: at a gain of 10, expect about 55 kHz of small-signal bandwidth. That is enough for 60 Hz rejection loops, low-frequency ADC anti-aliasing, and sensor conditioning, but not for switch-mode current sensing or high-speed data acquisition. The 100 µA supply current is the trade-off — this is a micropower part. Compare to a general-purpose op-amp like the TLV9351IDCKR, which offers 3.5 MHz GBW but draws 600 µA typical. The OPA187ID wins in battery-powered and loop-powered designs where every microamp counts; the TLV9351IDCKR wins where more bandwidth is needed and the power budget allows it.
The output swings rail-to-rail, which preserves dynamic range in low-voltage single-supply systems — a 5 V rail delivers a 0 V to 5 V output swing into a light load. The input common-mode range, however, stops 1.1 V below the positive rail (typical for a zero-drift architecture), so at 5 V supply the input cannot exceed about 3.9 V. This rules out high-side current sensing on a 5 V rail unless the shunt voltage is level-shifted.
The Zero-Drift series includes several channel-count and bandwidth variants; the OPA187ID is the single-channel 8-SOIC option.