250 mA LDO for noise-sensitive 4.5 V rails
The LP5907UVX-4.5/NOPB is a 250 mA low-dropout linear regulator from Texas Instruments, delivering a fixed 4.5 V output from a maximum 5.5 V input rail. It sits in the LP5907 family of ultra-low-noise LDOs aimed at analog and RF supply domains where ripple rejection matters more than efficiency.
PSRR is 90 dB at 100 Hz and rolls off to 60 dB at 100 kHz. That 90 dB at line frequency means the 100/120 Hz ripple from a rectified AC source is attenuated by a factor of 31,600 — a 10 mVpp ripple becomes 0.3 µVpp at the output. The 60 dB at 100 kHz still knocks down switching-regulator noise by 1000×, but above that frequency the attenuation drops further and a small ceramic cap on the input helps. Maximum dropout voltage is 200 mV at the full 250 mA load. With a 5 V input and 4.5 V output, the headroom is 500 mV — more than double the worst-case dropout, so the regulator stays in regulation even if the input dips to 4.7 V or the load current peaks. The 25 µA quiescent current (typical) keeps the self-heating negligible in a 4-DSBGA package with no exposed pad.
Industrial temperature range and protection
Built-in short-circuit and over-temperature protection are standard for this class, but the DSBGA package has no exposed thermal pad — the heat flows through the solder balls and PCB copper. A 2-layer board with 1 oz copper and a small via array under the package is usually adequate for 250 mA at 5 V in, but the dropout voltage at high temperature rises slightly (the 200 mV max is at 25°C).
Active lifecycle — sourcing for production
This is a current-production part suitable for new designs and volume builds.