Noise-sensitive analog rail — PSRR profile matters
The LP5907MFX-2.8/NOPB is a fixed 2.8 V output LDO from Texas Instruments, rated for 250 mA continuous output. Its PSRR starts at 90 dB at 100 Hz and rolls off to 60 dB at 100 kHz — this means it attenuates low-frequency ripple from a switching pre-regulator by a factor of ~30,000 at 100 Hz, dropping to ~1,000 at 100 kHz. For an analog front-end or precision ADC reference rail, that 90 dB floor at 100 Hz keeps 60 Hz mains harmonics and switching noise out of the signal path.
Dropout and headroom — the 250 mV ceiling
Maximum dropout voltage is 0.25 V at 250 mA load. This sets the minimum input-to-output differential: a 3.3 V rail feeding this LDO must stay above 3.05 V across the full load range, or the output falls out of regulation. The 25 µA quiescent current (Iq) keeps the part viable in battery-powered designs where the load spends most of its time in a light or sleep state.
Industrial temperature range and protection
Built-in over-temperature and short-circuit protection handle fault conditions without external supervisory circuitry. The enable pin (active high) allows the rail to be sequenced or gated by a GPIO or power-management IC.
Housed in a 5-pin SOT-23 (SC-74A) package, the LP5907MFX-2.8/NOPB occupies a compact footprint on the PCB. The supplier device package is SOT-23-5, a standard small-outline transistor package that reflows with typical lead-free profiles. The tape-and-reel variant (TR) is suited for automated pick-and-place assembly; a cut-tape (CT) option is also available for prototype or low-volume builds.