PSRR and dropout — what they mean for a noise-sensitive rail
The STMicroelectronics LD39020DTPU31R is a 200 mA fixed-output LDO in a 4-XDFN exposed-pad package, delivering a regulated 3.1 V from an input up to 5.5 V. The 0.35 V maximum dropout at the full 200 mA load means the input can sag to 3.45 V and still hold regulation, useful on a 3.6 V or 3.7 V lithium-ion rail through discharge.
Quiescent current and enable — always-on battery trade-offs
Quiescent current sits at 40 µA, low enough to leave the regulator biased continuously in a battery-powered sensor node without draining the pack overnight. The enable pin lets the system designer shut down the output rail entirely in deep sleep, dropping the load to near-zero. Protection features — over-current, over-temperature, and soft-start — are built in, so no external sequencing or current-limit circuitry is needed for the 200 mA rail.
Package and thermal: 4-DFN (1x1 mm) with exposed pad
The 4-DFN (1x1 mm) package with exposed pad is one of the smallest footprints for a 200 mA LDO.