The MIC5302-2.1YMT-TR is a 150mA positive fixed-output LDO from Micrel, delivering a regulated 2.1V from a maximum input of 5.5V. Its key differentiator is the 0.1V maximum dropout at full load — that means with a 3.3V rail you still hold 2.1V regulation through a 1.2V drop, leaving headroom for pre-regulator filtering or a long PCB trace. Quiescent current sits at 120µA, so it's not an ultra-low-Iq part for always-on wearables, but the combination of low dropout and moderate Iq suits it for local rail clean-up in sensor or audio supplies where the enable pin can gate the load when idle.
PSRR across the audio band
Power-supply rejection ratio is specified at 65dB at 1kHz, rolling off to 42dB at 20kHz. That's enough to knock down 100mVpp of 1kHz ripple from a switching pre-regulator to under 60µV at the output — relevant for powering a small analog front-end or a codec's analog supply. The roll-off above 10kHz is typical for a CMOS LDO without a dedicated noise-bypass pin; if you need >50dB at 100kHz, you'd step up to a higher-PSRR sibling like the MIC5317, but for audio-band noise the MIC5302 does the job.
Package and footprint — 4-TMLF (1.2x1.6mm)
Housed in a 4-lead TMLF package measuring 1.2mm x 1.6mm with an exposed pad. That's a very small footprint — roughly the size of two 0402 resistors side by side — so it fits into a compact sensor module or a handheld device PCB. The part is also offered in a 4-UFDFN variant, same land pattern.