Fixed 1.8 V rail for noise-sensitive loads
The Microchip MIC5366-1.8YC5-TR is a single-output, positive-voltage LDO regulator that delivers a fixed 1.8 V output at up to 150 mA. It operates from a 5.5 V max input and draws only 39 µA quiescent current. The part includes enable control and built-in over-current and over-temperature protection. Its 80 dB PSRR at 1 kHz, rolling off to 65 dB at 10 kHz, makes it a strong candidate for powering analog or RF circuitry where supply noise must be attenuated before it reaches the load.
Dropout headroom and thermal budget
Maximum dropout is 0.38 V at 150 mA, so a 3.3 V rail with 10% tolerance (down to 2.97 V) still holds the 1.8 V output in regulation through brownout or cold-crank events. The SC-70-5 package (SOT-353 footprint) limits continuous dissipation — at 125°C ambient and 150 mA load, the junction will approach the 125°C rated maximum unless the input-to-output differential is kept under about 1.5 V. For higher drop or higher ambient, derate the output current or add airflow.