1A fixed 5V LDO — the load-budget anchor
The MCP1826S-5002E/AB is a 1A fixed 5V LDO regulator from Microchip's MCP1826 family, in a TO-220-3 through-hole package. It delivers a regulated 5V rail from an input up to 6V maximum, with a dropout voltage of 0.4V max at full load — meaning the input must stay above 5.4V to maintain regulation under 1A draw. The fixed output eliminates the need for external feedback divider resistors, reducing BOM count and layout risk. Quiescent current is 220 µA typical, low enough for always-on rails in battery-backed systems.
PSRR and ripple rejection at line frequency
Power supply rejection ratio is 60 dB at 100 Hz — the dominant ripple frequency after full-wave rectification of 50/60 Hz mains. This means the output sees roughly 1 mV of ripple for every 1V of input ripple at that frequency, making the part suitable for post-rectifier filtering in linear supplies without a downstream LC stage. Protection features include over-temperature shutdown, short-circuit current limiting, and under-voltage lockout (UVLO). The UVLO threshold prevents the output from turning on until the input is high enough to keep the pass element in regulation, avoiding brownout glitches on power-up.
Thermal and environmental envelope
The TO-220-3 package allows direct heatsink attachment via the metal tab for high ambient or high load conditions. Lifecycle status is Active per Microchip, with full ROHS3 compliance — no end-of-life risk for ongoing production or new designs.