1.5 A LDO with a dropout that matters under load
The LP3882ESX-1.5 is a single-output, fixed 1.5 V positive LDO regulator from Texas Instruments, rated to deliver 1.5 A continuous. Its headline dropout is 0.27 V max at that full load — meaning the input rail can sit at 1.77 V and the output still holds regulation. Quiescent current is 30 µA typical, and the supply current maxes at 8 mA — a reasonable overhead for a 1.5 A part that is not in deep-sleep duty.
PSRR profile and what it means for a 1.5 V rail
Power-supply rejection ratio is listed at 80 dB at 120 Hz, rolling to 65 dB at 1 kHz. That 80 dB at line frequency means the regulator attenuates 120 Hz ripple from a rectified AC source by a factor of 10,000 — a 100 mV pk-pk input ripple becomes 10 µV at the output. By 1 kHz the rejection drops to 65 dB, still attenuating by a factor of ~1800. This profile suits a post-buck rail where the switching noise sits above 100 kHz; below that, the LDO cleans up the fundamental and its low-order harmonics. Protection features include over-current, over-temperature, and under-voltage lockout (UVLO). The UVLO prevents the output from turning on until the input rail is high enough to keep the pass device in regulation — a standard safeguard for a 1.5 V rail that cannot tolerate brown-out glitches.
DDPAK/TO-263-5 — board integration and thermal management
For a 1.5 A LDO dropping 0.5 V, that is 0.75 W to dissipate; the board copper area sets the junction temperature, not the package itself. The part is shipped in bulk tube, not tape-and-reel — a design-in consideration for high-volume pick-and-place lines that expect reel feed. Confirm the feeder setup before committing the BOM position.