Fixed 5V rail for automotive and industrial loads
The L4940V5 is a single-output positive fixed 5V LDO from STMicroelectronics, delivering up to 1.5A continuous with a maximum dropout of 0.9V at that current — meaning the input rail can dip as low as 5.9V and still hold regulation. That headroom matters when the supply is a battery or a lightly filtered rectifier. Its 68dB PSRR at 120Hz tells you it attenuates full-wave rectifier ripple by a factor of ~2500, which is the spec that keeps a sensitive analog front-end from seeing line-frequency hum on its supply rail.
Dropout, quiescent current, and protection
Maximum dropout is 0.9V at 1.5A — a genuine low-dropout figure that lets you run a 5V rail from a 6V battery or a 5.5V post-rectifier bus without losing regulation. The quiescent current sits at 8 mA typical, which is modest for a 1.5A-capable LDO but not micropower; expect 50 mA supply current max under load. Protection covers the three failure modes that kill a regulator in a wire harness: reverse polarity on the input, short circuit on the output, and over-temperature die shutdown. That set is what justifies the TO-220 package in a non-socketed through-hole mount — it's meant to be soldered into a board that sees field service.
No PCN or last-time-buy has been issued as of the current lifecycle review. The TO-220-3 package is a standard through-hole format that remains widely sourced across distribution channels.