Three-rail supervisor for ATX and industrial PSUs
The Texas Instruments TPS3513N is a multi-voltage supervisor that monitors three supply rails simultaneously: 3.3 V, 5 V, and 12 V. It asserts an active-low reset (open-drain output) when any monitored voltage falls below its threshold, and holds reset low for a minimum of 200 ms after all rails return to tolerance. This part is a direct fit for ATX power supplies, server backplanes, and industrial control boards that need a single-chip window watchdog on the main power buses.
The three voltage thresholds (3.3 V, 5 V, 12 V) cover the standard logic and analog rails found in most mixed-voltage systems. The 200 ms minimum reset timeout gives downstream microcontrollers, FPGAs, and DSPs enough time to complete their power-on reset sequences before the supervisor releases the reset line. If your processor requires a longer hold time, you will need an external delay or a supervisor with a programmable timeout. The open-drain output allows the reset signal to be wire-ORed with other reset sources (e.g., a manual reset button or a second supervisor). A pull-up resistor to the appropriate logic rail is required; the value is not critical but should be chosen to keep the output rise time within the downstream device's reset input specification.
Through-hole package and temperature grade
The TPS3513N comes in a 14-pin DIP package (14-DIP, 0.300-inch body width) with through-hole leads. This package is well suited for socketed prototyping, breadboarding, or rework in legacy equipment where surface-mount reflow is not an option.