Fixed 1.2 V rail for always-on and battery-backed loads
The MIC5232-1.2YD5-TR is a single-output positive LDO regulator from Microchip, delivering a fixed 1.2 V at up to 10 mA.
Dropout and headroom — what 0.3 V at 10 mA means on the board
Maximum dropout voltage is 0.3 V at the full 10 mA output. That means with a 1.5 V input rail (say from a Li-ion cell near end of discharge) the output stays regulated at 1.2 V. Below that input margin the regulator drops out of regulation — budget at least 0.3 V plus any ripple headroom when selecting the input source.
PSRR across the audio band — filtering budget for noise-sensitive rails
Power-supply rejection ratio runs 55 dB at 10 Hz and rolls to 35 dB at 1 kHz. That 20 dB slope across the audio band means the LDO handles low-frequency ripple well but needs additional post-filtering if the load is sensitive to switching-regulator hash above a few hundred hertz. For a 1.2 V analog rail (e.g. a MEMS microphone bias or a low-voltage ADC reference buffer), factor in the PSRR curve when sizing the input filter.
Package and temperature — field-swap realities
Housed in a TSOT-23-5 (SOT-23-5 Thin) package, it is a five-pin surface-mount part with a fixed output — no external resistor divider needed.