150 mA LDO, 2.5 V fixed — the dropout margin that matters
The MAX8867EUK25 is a single-output positive LDO from Analog Devices, delivering 150 mA at a fixed 2.5 V. The key fit parameter is the 0.165 V max dropout at full load — the input rail must stay at least 165 mV above 2.5 V across the load range, or the output falls out of regulation. For a 3.3 V bus feeding this LDO, the margin is about 0.635 V, which covers brownout dips down to roughly 2.7 V before dropout becomes a concern. Quiescent current is 180 µA typical, with a maximum supply current of 100 µA — the difference suggests the internal bias draws roughly 80 µA, and the remaining 100 µA is the output stage overhead. This Iq is moderate for a 150 mA LDO; it is not an ultralow-power part for always-on battery nodes, but it is reasonable for a regulated rail in a sensor module or industrial control board where the load is intermittent.
PSRR at 10 kHz — what 63 dB actually buys you
The 63 dB PSRR at 10 kHz means the LDO attenuates ripple on the input by a factor of roughly 1400 at that frequency. If the input has 100 mVpp switching noise from a nearby buck converter, the output sees about 70 µVpp — clean enough for a 10-bit ADC reference or a sensitive analog front-end. PSRR rolls off above 10 kHz, so upstream filtering ahead of the LDO is still advisable if the switching noise is above 100 kHz.
Protection set and temperature grade
The MAX8867EUK25 includes over-current, over-temperature, reverse polarity, and short-circuit protection — a solid set for a board that may see a miswired connector or a stalled load. Package is SC-74A (SOT-753) with the supplier device package listed as SOT-23-5 — these are effectively the same footprint: 5-pin, 0.95 mm pitch, 2.9 x 1.6 mm body. The enable pin (Control Features) allows the LDO to be shut down externally, pulling the output to high-Z and dropping the supply current to near zero.