Fixed 5 V rail with 0.1 V dropout margin
The LP3985IM5-5.0/NOPB: The 0.1 V maximum dropout at full load means the input can sag to 5.1 V before the output falls out of regulation — a critical margin for 5 V rails fed from a battery near its end-of-discharge or from a loosely regulated 5.5 V intermediate bus.
PSRR profile and noise-sensitive loads
Power-supply rejection ratio is 50 dB at 1 kHz, rolling off to 40 dB at 10 kHz — this is the band where switching-regulator ripple and digital clock feedthrough typically sit, so the LP3985 provides meaningful attenuation for analog front-ends, RF oscillators, or ADC reference rails powered from a noisy upstream converter.
Protection set and control interface
Built-in protection covers over-current, over-temperature, and short-circuit events — the regulator shuts down and auto-recovers when the fault clears, so a momentary output short on a test probe won't latch the rail dead. An enable pin allows the output to be gated by a GPIO or power-good signal — useful for sequencing multiple rails or shutting down the 5 V domain in a sleep state.
Housed in an SC-74A (SOT-23-5) package, the LP3985IM5-5.0/NOPB occupies a small PCB footprint — the 5-pin SOT-23 fits in tight layouts where board space is at a premium.
ROHS3 compliant — the NOPB suffix confirms lead-free and halogen-free construction, which clears EU and many Asian regulatory gates without an exemption expiry.