150 mA fixed 2.8 V LDO — headroom and dropout
The LP2985IM5X-2.8 is a single-output positive LDO regulator delivering a fixed 2.8 V at up to 150 mA. Input voltage range extends to 16 V max, so the part can run from a 12 V intermediate bus or a 5 V rail without a pre-regulator. The 95 µA quiescent current keeps the self-consumption low in always-on or battery-backed applications.
PSRR and noise rejection at 1 kHz
PSRR is specified at 45 dB at 1 kHz — this is the rejection of ripple on the input at that frequency. For a 100 mV p-p ripple at 1 kHz, the output sees roughly 560 µV p-p. At higher frequencies the PSRR rolls off, so upstream switching noise above 100 kHz will pass through unless filtered ahead of the LDO.
Protection features and temperature range
The enable pin allows external on/off control, which can be used to sequence rails or reduce quiescent draw in shutdown. Operating temperature spans -40°C to 125°C, covering automotive under-hood and industrial enclosure environments. The SOT-23-5 package (SC-74A) is a common footprint — the copper pad area under the IC sets the thermal resistance, so a solid ground plane on the PCB helps keep the junction temperature within limits at 150 mA.