Fixed 5V rail, 100mA ceiling
The UA78L05AILPRE3 is a fixed 5V positive-output linear regulator rated for 100mA continuous output current. That 100mA ceiling is the hard limit for the load — anything pulling more than that on the 5V rail will pull the output out of regulation or hit the current limit. Input voltage can go up to 20V, giving plenty of headroom for a 5V rail from a 12V or 9V supply. The dropout voltage is 1.7V max at 40mA load — so the input needs to stay at least 1.7V above 5V to keep the output regulated. Below that, the output follows the input minus dropout.
Field-swappable TO-92-3 package
Through-hole TO-92-3 (TO-226AA) with formed leads — the same three-pin footprint as the classic 78L05. No hot-air station needed; it swaps with a soldering iron and a desoldering pump. The formed leads drop into the same board pattern as the standard TO-92, so it is a direct replacement on existing boards.
Protection set covers the common failure modes
Built-in over-current, over-temperature, reverse polarity, and short-circuit protection. The over-temperature shutdown kicks in before the die hits its thermal limit — useful if the load shorts or the ambient spikes. Reverse polarity protection means a backwards battery connection on the input won't instantly kill the regulator. PSRR is 49dB at 120Hz — that is the ripple rejection on the input. A 49dB rejection means the output ripple is about 1/280th of the input ripple at that frequency. Good enough for most analog supply rails, but if you need cleaner power for a precision ADC front-end, you will want a post-filter stage.
Active production, industrial temp grade
ROHS3 compliant — no exemptions for lead in solder, so it ships clean for EU and California markets.