Fixed 5 V rail in a TO-92-3 — what the LP2950ACZ-5.0/NOPB delivers
Dropout and quiescent current — the margin story
Maximum dropout voltage is 0.6 V at 100 mA load, meaning the input rail needs at least 5.6 V to maintain regulation at full output. Quiescent current is 120 µA typical, which keeps the self-heating low in the TO-92-3 package — no heatsink needed for most loads, as long as the input-to-output differential stays under a few volts. Input voltage can go up to 30 V absolute maximum, so the part tolerates unregulated supplies or battery voltages well above the 5 V rail. Protection features include over-current and over-temperature shutdown, which guard against output shorts or thermal runaway in confined enclosures.
The TO-92-3 package is not board-space-efficient, but it is easy to hand-solder and replace in field repairs.
Sourcing posture — active and available
No official second-source or pin-compatible replacement is listed, but the LP2950 family includes other fixed-voltage variants (3.0 V, 3.3 V, adjustable) in the same TO-92-3 footprint if the design needs a different rail.