Regulator identity and key parametrics
The MCP1825-1802E/AT is a single-output, fixed 1.8 V LDO from Microchip Technology's MCP1825 family, delivering up to 500 mA in a TO-220-5 through-hole package. Power-supply rejection ratio is 60 dB at 100 Hz, meaning the regulator attenuates 100 Hz ripple (e.g., from a mains rectifier) by a factor of 1000 — relevant for analog front-ends or audio circuits that share a rail with a switching converter.
Protection and control features
On-chip protection includes over-temperature shutdown, short-circuit current limiting, and under-voltage lockout (UVLO) — the UVLO prevents the output from turning on until the input is high enough to keep dropout within spec, avoiding brown-out operation. The Enable and Power Good control pins allow sequencing: pulling EN low puts the output into shutdown (quiescent current drops to near zero), and the PG flag asserts when the output is within regulation — useful for power-rail sequencing in multi-rail designs.