The BD3925FP-CE2 delivers 55 dB of power-supply rejection at 120 Hz, the fundamental ripple frequency from a full-wave rectified line. That means a 1 Vpp ripple on the input is attenuated to roughly 1.8 mVpp on the output — clean enough to feed sensitive analog front-ends or microcontroller ADCs without additional post-filtering.
Load and headroom envelope
Rated for 500 mA continuous output with a maximum input voltage of 36 V, this LDO covers the common automotive battery rail (12 V nominal, up to 36 V during load-dump transients). Dropout voltage is 0.48 V max at 200 mA load, so a 5 V output rail needs only 5.48 V at the input to stay in regulation — useful when the battery dips during cold-crank. Quiescent current is 90 µA typical, low enough for always-on modules like body controllers or keyless-entry receivers that draw from the battery even when the ignition is off. The output is adjustable via external feedback resistors, with a tracking minimum voltage that follows the reference. Enable pin allows the regulator to be shut down entirely, cutting Iq to near zero in sleep modes.
Temperature grade and deployment context
This qualifies the part for under-hood electronics, engine-control modules, and transmission controllers where ambient temperatures exceed 105°C. The TO-252-5 (DPak) package with exposed tab allows the die heat to be conducted to a PCB copper plane; the tab is the ground path, so the thermal pad on the board must be tied to the ground plane with multiple vias for effective heat spreading.