Triple-rail LDO for mixed-voltage designs
The MIC5387-SG4YMT-TR is a triple-output low-dropout linear regulator from Microchip Technology, delivering fixed voltages of 1.2 V, 1.8 V, and 3.3 V from a single device — a single package powers the core, I/O, and analog rails on a mixed-voltage board. Each output is rated for 150 mA continuous, enough for a small MCU plus its peripheral and sensor supply without a second regulator.
PSRR and noise rejection across frequency
Power-supply rejection ratio is specified at 70 dB at 1 kHz, dropping to 60 dB at 10 kHz — the 10 dB roll-off across that decade means upstream switching noise above 10 kHz will couple through unless filtered ahead of the LDO, so the input rail should be clean or have a ferrite bead in front. The 40 µA quiescent current and 120 µA maximum supply current keep the regulator's own draw low, suiting battery-powered or always-on subsystems where every microamp counts.
Industrial temperature grade and protection
Built-in over-current and over-temperature protection means the regulator shuts down before the die exceeds safe junction temperature; the enable pin lets a system controller sequence the rails on and off.
The dropout voltage is 0.38 V max at 150 mA on the 1.2 V and 1.8 V rails, 0.31 V max on the 3.3 V rail — headroom above the output voltage must stay above these figures across load and temperature to keep regulation.