70 mA LDO with 30 V input ceiling and wideband PSRR
The MCP1790-3002E/DB is a single-output positive LDO regulator from Microchip Technology, delivering a fixed 3 V rail at up to 70 mA.
PSRR profile and quiescent current trade-off
Power-supply rejection ratio holds 90 dB at 100 Hz and drops to 80 dB at 1 kHz — this means the regulator attenuates 100 Hz line ripple (from a rectified mains supply) by a factor of 31,600, and still knocks down 1 kHz switching noise by 10,000×. For a sensitive analog front-end powered from a noisy 24 V rail, this PSRR floor keeps the output clean enough to avoid injecting ripple into the signal chain. Quiescent current is 130 µA typical, rising to 210 µA maximum under full supply — low enough to keep the regulator's own draw negligible in a battery-backed system that spends most of its time in sleep mode. The 1.3 V maximum dropout at 70 mA means the input must stay above 4.3 V to hold the 3 V output in regulation; a 5 V rail provides 0.7 V of headroom.