What the 55 dB PSRR means for your analog rail
The LDK120C08R holds 55 dB of power-supply rejection across a 120 Hz to 10 kHz band — that is wideband enough to clean up ripple from a switching regulator feeding a sensitive ADC or op-amp reference. Below 55 dB at 10 kHz, the LDO starts to let high-frequency switching noise through, so keep the upstream converter's fundamental below that corner. Fixed 0.8 V output at 200 mA, with a maximum dropout of 0.3 V at full load — the input rail needs at least 1.1 V to hold regulation. That makes it a candidate for powering a low-voltage digital core or a 0.8 V I/O bank from a 1.2 V or 1.5 V intermediate bus.
Field-swap and board-fit note
SOT-323-5 (SC-70-5) package — 5 pins, about 2.0 × 2.1 mm footprint.
The LDK120 family shares the same die and package across output voltages; the only difference is the trimmed bandgap resistor that sets Vout.