5V rail watchdog for automotive ECUs
The Texas Instruments TPS389050GQDSERQ1 is a simple reset/power-on reset IC designed to monitor a single 5V supply rail and assert an active-low reset signal when the voltage drops below the threshold. The open-drain output allows wired-OR connection with other fault signals, and the low quiescent current makes it suitable for always-on modules that must not drain the battery during key-off.
Threshold voltage — confirming the rail match
The reset threshold is set at 5V, meaning the device monitors a nominal 5V supply and asserts reset when the rail falls below that level. This is a fixed-threshold part, not adjustable via external resistors, so the BOM decision is straightforward: if your system runs a 5V rail that needs supervision, this IC is a direct fit. The active-low output (RESET) goes low when the monitored voltage drops below threshold and stays low for the duration of the fault; when the supply recovers, the output releases after a deglitch timeout.
Package and footprint — 6-WSON (1.5x1.5)
6-WSON package, 1.5 mm by 1.5 mm, surface mount only.
This means it remains a current-design-in part suitable for new automotive programs and ongoing production. There is no LTB risk or forced migration to a successor at this point.