Three-rail supervisor for ATX and industrial power sequencing
The Texas Instruments TPS3513D is a multi-voltage supervisor that monitors three supply rails — 3.3V, 5V, and 12V — with fixed undervoltage thresholds. It asserts a common active-low reset output when any monitored voltage falls below its threshold, and holds reset for a guaranteed 200 ms minimum after all rails return to tolerance. This part is the standard choice for ATX power supply sequencing, industrial control boards, and any multi-rail system that needs a single-chip power-good indicator.
Fixed thresholds and reset timing — no programming, no surprises
The three monitored thresholds are factory-set to 3.3V, 5V, and 12V. There is no adjustable pin or resistor divider — the thresholds are fixed, so the BOM must match these nominal rail voltages. The reset output is open-drain (open-collector), which lets you pull it up to any logic voltage independent of the monitored rails. This is handy in mixed-voltage systems where the supervisor runs from a 12V bias but the reset signal feeds a 3.3V microcontroller. The reset timeout is specified as a minimum of 200 ms. This ensures the downstream processor stays in reset long enough for all supply rails to stabilise after power-up or after a brownout recovery. The 200 ms floor is a datasheet guarantee — actual timeout may be longer, but never shorter. If your processor requires a specific reset pulse width, budget for the minimum.
14-SOIC footprint and industrial temperature range
This is a common, easy-to-route surface-mount footprint that fits standard pick-and-place assembly. No derating needed for ambient temperatures up to 85°C.
Texas Instruments lists it as current production with no announced end-of-life. For procurement, this means no last-time-buy risk and no forced redesign for the foreseeable future.