3.3 V fixed LDO for noise-sensitive rails
The Microchip MCP1801T-3302I/OT is a single-output, fixed 3.3 V positive linear regulator rated for 150 mA continuous output. It targets applications where a clean analog or digital supply rail is needed from a 10 V max input — think sensor front-end supplies, MCU analog VDDA rails, or post-switcher clean-up for RF modules. The 70 dB PSRR at 10 kHz is the headline spec here: that is the frequency where many buck converters ring, so this LDO knocks down the ripple by a factor of 3000 while burning only 50 µA quiescent current.
Dropout headroom and load budget
Maximum dropout is 0.25 V at 100 mA load, meaning a 3.55 V input holds regulation with margin before the output falls out. At the full 150 mA rating the dropout rises — budget at least 350 mV headroom for the worst case across temperature. The 50 µA quiescent current is typical; at light loads (tens of µA) the LDO does not waste battery charge, making it usable in always-on sensor nodes or remote IoT endpoints that spend most of their time in sleep.
Package, temperature, and protection
Housed in a 5-pin SOT-23-5 (SC-74A), this is a surface-mount part for automated assembly. On-chip over-current protection is included; there is no thermal shutdown listed, so the board layout should not rely on the die to self-protect during a sustained short — keep the trace impedance low and the output capacitance reasonable. The Enable pin (active-high logic) lets a system microcontroller gate the rail off in standby, saving the 50 µA Iq.
Sourcing and compliance status
Microchip lists this part as Active, so there is no looming last-time-buy or obsolescence risk for production programs. ROHS3 compliant — no exemptions for lead in solder, which simplifies EU and global market compliance.