Micropower op-amp for always-on sense circuits
The Microchip MCP6231UT-E/OT is a single-channel general-purpose op-amp that draws just 20 µA of supply current while delivering a 300 kHz gain-bandwidth product. The rail-to-rail output stage lets the signal swing close to the supply rails, which is useful when running from a 1.8 V rail where every millivolt of headroom matters. Input bias current is 1 pA, so high-impedance sources like photodiodes or pH probes won't see loading error.
The SOT-23-5 package is a compact footprint for space-constrained boards.
The 0.15 V/µs slew rate limits large-signal bandwidth; a 1 V peak-to-peak sine wave starts to distort above roughly 24 kHz. That is fine for DC or low-frequency sensor outputs (temperature, pressure, strain gauges) but not for audio or fast ADC drive. The 300 kHz GBWP means closed-loop gain of 10 gives a 30 kHz small-signal bandwidth — adequate for most transducer conditioning. If you need faster settling, the MCP6281 (5 MHz GBWP, 2.5 V/µs slew rate) is a direct drop-in in the same SOT-23-5 footprint, though it draws 400 µA supply current.