Noise-sensitive rail regulator with 60 dB PSRR
The LP2989IMX-2.5/NOPB is a fixed 2.5V output LDO from Texas Instruments, rated for 500 mA continuous output current. Its 60 dB PSRR at 1 kHz means it rejects switching noise from upstream DC-DC converters well enough to feed sensitive analog rails — ADC references, op-amp supplies, or RF front-ends — without an additional post-filter stage.
Dropout and quiescent: the real BOM-fit numbers
Maximum dropout is 0.65 V at the full 500 mA load. If the input rail is 3.3 V, the headroom is 0.8 V — enough margin across temperature and line variation. Quiescent current is 175 µA typical, which matters for always-on peripherals where the regulator's own draw competes with the load's sleep current. Operating temperature spans -40°C to 125°C, so this part handles both cold-start and under-hood ambient without a grade change. Built-in protection covers overcurrent, overtemperature, and short-circuit events — the regulator folds back rather than latching off or failing open.