150 mA LDO for a clean 1.8 V rail
The LP5900SDX-1.8/NOPB is a single-output, fixed 1.8 V LDO delivering 150 mA from a 5.5 V max input rail. Quiescent current is 50 µA typical, with a maximum supply draw of 230 µA. For a battery-powered sensor that spends most of its time in a low-power state with the regulator enabled, that Iq is the floor the system sees between active bursts.
PSRR profile and noise-sensitive loads
Power-supply rejection ratio starts at 85 dB at 100 Hz and rolls off to 40 dB at 100 kHz. That means low-frequency ripple from a mains-derived DC rail is attenuated by a factor of ~18,000, while switching-regulator noise at a few hundred kHz passes through with only 100× rejection. If the downstream load is an analog front-end or a PLL that runs off the 1.8 V rail, the upstream switcher's ripple needs to be below the LDO's attenuation floor at the switching frequency. The 6-WSON package with exposed pad (2.2 × 2.5 mm) keeps the thermal resistance low enough for 150 mA at 85 °C ambient, provided the PCB pad has a solid via array to an internal ground plane. The enable pin lets a system controller gate the rail entirely, cutting the supply current to near zero when the 1.8 V domain is idle.
Active lifecycle and sourcing
Supplied in tape-and-reel or cut-tape options. The 6-WSON footprint is shared across the LP5900 family, so a board layout for this order code accepts other fixed-voltage variants of the same regulator without a PCB spin.