Adjustable 50 mA LDO for tight rails
The LP2980IM5X-ADJ is a 50 mA adjustable positive LDO from Texas Instruments in a SOT-23-5 package. Its 0.22 V maximum dropout at 50 mA means it can regulate from a supply rail as low as 1.45 V above the output — critical when the input is a 3.3 V or 5 V rail already loaded with other regulators. The 95 µA quiescent current keeps the standby draw low for battery-powered instrumentation and always-on sensor nodes.
Ripple rejection and protection envelope
PSRR is 63 dB at 1 kHz — enough to attenuate typical switching-regulator ripple by a factor of 1400. For noise-sensitive analog front ends fed from a 1 MHz switcher, the rejection above 100 kHz is lower; plan for a post-LDO LC filter or a higher-PSRR alternative like the LP5907 (90 dB at 100 Hz to 100 kHz). Built-in protection covers over-current, over-temperature, and short-circuit events. The enable pin lets a system controller shut down the LDO, dropping supply current to near zero when the load is idle.
The SOT-23-5 footprint (SC-74A) is a common low-profile land pattern, compatible with reflow soldering and standard pick-and-place.