Automotive-grade 3.3 V rail for engine-control and body-electronics power
The Infineon TLS850B0TEV33ATMA1 is a fixed-output linear regulator from the OPTIREG™ family, delivering 3.3 V at up to 500 mA from a 40 V maximum input rail. The AEC-Q100 qualification places it in the -40°C to 150°C junction temperature band — the full under-hood and engine-bay ambient range. A 25 µA quiescent current keeps the regulator's own draw low enough that a continuously-powered ECU module does not drain the battery during key-off periods.
Dropout headroom and PSRR for noise-sensitive loads
Maximum dropout voltage is 0.6 V at 250 mA — the input rail must stay at least 0.6 V above 3.3 V across the full load range to maintain regulation. For a nominal 5 V supply, that leaves 1.1 V of headroom; a 3.3 V rail derived from a 3.8 V battery near end-of-discharge still has 0.5 V margin. The 63 dB PSRR at 100 Hz attenuates alternator ripple and switching-converter feedthrough by a factor of roughly 1400 — sufficient for analog sensor supply rails in an engine management unit.
Enable control and protection for fault-tolerant system design
An Enable pin allows the regulator output to be gated by a system supervisor or ignition signal — the output stays off until the enable threshold is crossed, preventing unpowered loads from back-driving the rail during startup sequencing.
TO-252-5 DPAK package and board-level integration
The PG-TO252-5 package is a 4-lead DPAK with an exposed tab — the tab is the ground path and the primary heat sink.