What this regulator does in a through-hole design
The LM317LZ-AP is an adjustable positive voltage regulator delivering up to 100 mA from a 40 V maximum input, with an output adjustable from 1.2 V to 37 V via two external resistors. Its PSRR of 80 dB to 65 dB at 120 Hz provides meaningful ripple rejection for analog supply rails, sensor bias, or audio preamp stages where line-frequency hum must be attenuated. Built-in protection covers over-current, over-temperature, and short-circuit conditions, reducing the risk of failure in single-supply applications.
Parametric fit: current, voltage, and temperature
Rated for 100 mA continuous output, this part suits low-current rails — op-amp supplies, reference bias, or local post-regulation — not main power buses. Operating temperature spans 0 °C to 125 °C, which covers commercial and most industrial environments but not extended automotive or mil-spec ranges. Quiescent current is 5 mA typical; for battery-powered designs, the dropout voltage (not listed in evidence) and Iq should be verified against the load profile.
The TO-92-3 through-hole package (formed leads) is widely stocked and compatible with legacy sockets and hand-assembly processes.