Supply rail and dropout headroom
The TLE46782ELXUMA1: Rated for 45 V input max, this LDO sits on an automotive 12 V or 24 V bus and survives load-dump transients without an external clamp — the internal FET handles the surge. Dropout is 0.3 V max at 150 mA output, so the input rail must stay at least 300 mV above 5 V across the full load range. At cold crank where the battery dips to 6 V, the 5 V output holds regulation as long as the input stays above 5.3 V.
Ripple rejection and noise budget
65 dB PSRR at 100 Hz means the alternator ripple at the fundamental frequency is attenuated by a factor of ~1800 — a 1 Vpp ripple on the input becomes roughly 0.55 mVpp at the output, clean enough for the analog supply rail of an engine ECU's sensor interface.
Protection and supervisory features
Built-in over-current, over-temperature, reverse polarity, and short-circuit protection let the regulator survive a miswired harness or a stalled load without latching off — it recovers when the fault clears. The integrated reset and watchdog supervisor mean this single IC replaces a separate voltage monitor and watchdog timer in safety-critical designs — useful for ASIL-capable ECUs that need a guaranteed reset on brownout.
AEC-Q100 qualified across -40°C to 150°C ambient — this is the full under-hood temperature band. An engine-bay ECU that sees 125°C on a hot soak still has margin to the 150°C limit. Part of the OPTIREG™ family, designed for automotive power supply chains where a pre-regulated 5 V rail feeds the MCU, CAN transceiver, and sensor bias.