2.5V fixed LDO for automotive and industrial rails
The LP38691SD-2.5/NOPB is a single-output positive linear regulator from Texas Instruments, delivering a fixed 2.5V output at up to 500mA. The 55µA typical quiescent current keeps the regulator's own draw low enough for always-on modules in battery-backed systems.
PSRR and noise rejection at line frequency
Power supply rejection ratio is specified at 55dB at 120Hz, the fundamental ripple frequency from a full-wave rectified 60Hz mains. Input voltage range extends to 10V maximum, covering the nominal 12V automotive bus with margin for cold-crank dips down to 4.5V as long as the input stays above the dropout headroom. Over-temperature protection is built in, with no reverse-current or current-limit features — the protection is thermal-only.
Package, footprint, and board integration
The LP38691SD-2.5/NOPB comes in a 6-WDFN exposed pad package (supplier device package 6-WSON, 3x3mm). Mounting is surface mount only, with packaging options of Tape & Reel or Cut Tape for prototyping. The 6-pin footprint is compact enough for space-constrained ECU modules but requires a thermal via array under the pad for heat sinking.