1.5 A LDO, 0.8 V fixed — tight dropout, clean output
The LP38855T-0.8/NOPB is a 1.5 A low-dropout linear regulator from Texas Instruments with a fixed 0.8 V output. It comes in a through-hole TO-220-5 package with formed leads — field-swappable with basic tools, no hot-air station needed. Maximum dropout is 180 mV at full load, meaning the input rail needs to stay above 0.98 V to keep the output in regulation at 1.5 A. That tight headroom is useful when the input comes from a switching pre-regulator with only a few hundred mV of margin.
PSRR: 80 dB at 120 Hz, 58 dB at 1 kHz
Power-supply rejection ratio is 80 dB at 120 Hz, dropping to 58 dB at 1 kHz. The 80 dB at 120 Hz is strong enough to knock down the 100/120 Hz ripple from a mains rectifier by a factor of 10,000 — so a post-regulator after a bulk capacitor can deliver a clean rail for analog front-ends. Above 1 kHz the rejection rolls off, so switching noise at 100 kHz or higher passes through largely unattenuated. Quiescent current is 300 µA typical — fine for always-on industrial control rails, but not intended for battery-powered sleep circuits where every microamp counts. The enable pin lets you shut down the regulator entirely when the rail is not needed.
Protection and temperature range
Built-in protection covers over-current, over-temperature, and short-circuit — no need for external foldback or thermal-shutdown circuitry. Maximum input voltage is 5.5 V, so this regulator works off standard 3.3 V, 5 V, or battery rails without a separate pre-regulator. The 1.5 A output is enough to power a core rail on a mixed-signal board or a post-regulator after a switcher.
ROHS3 compliant, so it fits EU and global BOMs without exemption paperwork.