Fixed 5 V rail from up to 20 V input
The UA78L05AILPR from Texas Instruments is a single-output positive linear regulator delivering a fixed 5 V at up to 100 mA. With a maximum input of 20 V, it steps down a higher unregulated or semi-regulated rail to a clean 5 V bus for MCUs, sensors, or interface logic on a through-hole board.
PSRR and noise rejection at line frequency
Power-supply rejection ratio is 49 dB at 120 Hz — this is the ripple-rejection figure at the fundamental of a full-wave-rectified 60 Hz mains. For a downstream ADC or analog front-end powered from a lightly loaded 5 V rail, that 49 dB attenuation cuts a 1 Vpp input ripple to roughly 3.5 mVpp at the output, enough to keep line-frequency hum out of the signal chain.
Protection set and temperature grade
Built-in protection covers over-current, over-temperature, reverse polarity, and short-circuit — the regulator survives a sustained output short without damage and recovers when the fault clears.
Through-hole TO-92-3 — board-fit note
Housed in the TO-226-3 / TO-92-3 package with formed leads, the part is a three-pin through-hole device. The TO-92 body is narrow enough for tight layouts but the lead pitch is 2.54 mm (0.100 inch) — match the pad spacing to avoid rework.