500 mA LDO with 40 V input ceiling
The Infineon TLS850F0TAV50ATMA1 is a single-output positive LDO in the OPTIREG™ family, delivering a fixed 5 V at up to 500 mA continuous output.
59 dB PSRR and 5 µA quiescent current
Power supply rejection ratio is 59 dB at 100 Hz — this is the ripple attenuation from a rectified 50/60 Hz mains or an alternator's output. At 59 dB, a 1 Vpp ripple on the input drops to roughly 1.1 mVpp on the output, which keeps noise-sensitive loads like sensor front-ends or CAN transceivers clean. In a battery-backed always-on module (e.g., an ECU keep-alive supply), the 5 µA Iq adds negligible drain — the regulator's own draw is below the self-discharge rate of a typical automotive coin cell. Dropout voltage is 0.425 V max at 250 mA output — the headroom between input and 5 V output must stay above that figure at full load, or the output falls out of regulation. At 500 mA the dropout is higher; the datasheet's dropout curve (not reproduced here) governs the actual margin.
Built-in watchdog and protection features
Control features include an Enable pin for shutdown, a Reset output for power-good sequencing, and a Watchdog timer that monitors the microcontroller's health. The watchdog expects a periodic toggle on its input; if the MCU hangs, the regulator asserts Reset and holds the system in reset until the watchdog is serviced — this eliminates a separate external watchdog IC in many designs. Protection is comprehensive: over-current limiting, over-temperature shutdown, and short-circuit protection are all integrated. The thermal shutdown threshold is above the 150°C junction rating, so a sustained overload cycles the output until the fault clears.
PG-TO263-7-1 package and board fit
The package is a 7-lead TO-263 (D²Pak) with a large exposed copper tab — the PG-TO263-7-1 variant. The tab is electrically connected to ground (the output is positive, so no isolation concern). Surface-mount assembly: the TO-263 footprint is standard and hand-solderable with a moderate iron or hot-air station — the tab needs a good solder fillet for thermal transfer. No underfill is required for automotive vibration levels per AEC-Q100.