117 dB PSRR — what it means for a sensitive analog rail
The LT3045EMSE#PBF delivers 117 dB of power-supply rejection at 120 Hz, tapering to 53 dB at 10 MHz. That rejection holds across the full 500 mA output range without an external feed-forward capacitor, which means a downstream ADC or VCO sees the regulator's own noise floor rather than the switching ripple from a buck converter upstream.
500 mA output and dropout headroom
Rated for 500 mA continuous output with a maximum dropout of 0.45 V at full load. The input rail must stay at least 0.45 V above the programmed output across the full load and temperature range; a 3.3 V output needs a 3.75 V minimum input, pushing the supply rail to 5 V or a boost stage in many low-noise designs. Quiescent current is 20 µA typical, rising to 25 mA at maximum supply current — the 20 µA figure dominates in battery-backed always-on rails where the load is light and the regulator spends most of its time in regulation. Output voltage is adjustable from 0 V to 15 V via a single resistor divider; the reference operates down to 0 V, so the part can serve negative rail generation or power a precision DAC reference that must track to ground.