TO-252 surface-mount adjustable regulator — 1.5 A continuous
The Texas Instruments LM317AMDT/NOPB is a three-terminal adjustable positive voltage regulator in a TO-252-3 (DPak) surface-mount package, rated for 1.5 A output current and a 40 V maximum input. It delivers an adjustable output from 1.25 V up to 37 V, set by two external resistors — the classic LM317 architecture in a footprint that suits automated assembly and moderate power dissipation.
PSRR and ripple rejection at line frequency
Power-supply rejection ratio is listed at 80 dB to 65 dB at 120 Hz — the higher figure at light loads, the lower at full 1.5 A output. For a 1 V peak-to-peak ripple on the input at 120 Hz, the output ripple is roughly 100 µV to 560 µV, depending on load. That is clean enough for most analog and mixed-signal rails; if you need better rejection above a few kilohertz, a post-filter or an LDO with higher bandwidth is warranted.
Protection suite — over-current, over-temperature, short-circuit
Built-in over-current limiting, thermal shutdown, and short-circuit protection mean the regulator survives output faults without external clamp diodes in most designs. The quiescent current is 10 mA typical, which matters for always-on or battery-backed rails.