The LM2931AD33R delivers 78 dB of power-supply rejection at 120 Hz, the fundamental ripple frequency from a full-wave rectifier. That attenuation factor of roughly 8000× means a 1 Vpp ripple on the input collapses to about 125 µVpp on the 3.3 V output — a clean enough rail for most analog front-ends and sensor bias circuits without a post-filter. The 26 V absolute-max input gives headroom for 12 V and 24 V industrial buses with transient margin. Quiescent current is 1 mA typical — not the lowest in class, but acceptable for always-on control rails where the load current dominates the power budget. The internal current-limit and thermal-shutdown protection handle fault conditions without external clamp diodes.
Temperature grade and package fit
Rated for -40 to 125 °C junction temperature, the LM2931AD33R spans the industrial and automotive temperature envelope — suitable for under-hood electronics, outdoor telecom, or factory-floor control modules that see 105 °C ambient with self-heating margin. The surface-mount package is rework-friendly with a standard hot-air profile and does not require X-ray inspection after reflow.
Lifecycle and compliance
The base number LM2931 covers a family of fixed and adjustable output voltages in the same pinout, so a BOM change to a different voltage variant shares the same PCB footprint. ROHS3 compliant per the manufacturer — no exemptions that would trigger a compliance review for EU or UKCA markets.