250 mA LDO — noise rejection and headroom
The LP5907MFX-3.3/NOPB is a fixed 3.3 V output LDO rated for 250 mA continuous output. Its PSRR starts at 90 dB at 100 Hz and rolls off to 60 dB at 100 kHz, which means it cleans up ripple from a switching regulator upstream — the 60 dB floor at 100 kHz still attenuates a 1 mV ripple to 1 µV at the output, keeping noise-sensitive analog rails clean. Maximum dropout is 250 mV at the full 250 mA load, so the input rail needs at least 3.55 V to maintain regulation. Quiescent current sits at 25 µA typical — low enough that in a battery-powered sensor waking once a minute, the regulator's own draw doesn't dominate the sleep budget. Operating temperature spans -40°C to 125°C, covering industrial enclosures and under-hood automotive ambient without derating. The SOT-23-5 package is small enough for tight layouts but still hand-solderable with a fine-tip iron — no hot-air station needed for a field swap.
Active lifecycle — no LTB clock ticking
Protection features include over-temperature shutdown and short-circuit current limiting — the output folds back under fault, then recovers automatically when the condition clears. No external protection diode needed for most loads under 250 mA.