Two-rail watchdog for 3.3V and 5V supplies
It is designed for systems that require sequential or simultaneous monitoring of both a 3.3V and a 5V rail — common in mixed-voltage designs with FPGAs, DSPs, or MCUs that power I/O banks from one rail and the core from the other.
Thresholds that match the rails
The monitored thresholds are 2.93V and 4.55V. The 2.93V threshold suits a nominal 3.3V supply with a typical undervoltage trip around 2.93V — about 11% below nominal. The 4.55V threshold matches a 5V rail with a similar margin. If your system runs 3.3V and 5V, these thresholds are a direct fit; if you need tighter tolerance monitoring (e.g., a 1.8V or 2.5V rail), this part does not cover it.
140 ms reset hold — enough for most supplies
The reset timeout is 140 ms minimum. It is short enough that the system wake-up delay is acceptable for industrial controllers and telecom line cards, but if your design requires a longer reset pulse (e.g., for a slow-start power module), you will need an external timer or a supervisor with a programmable delay.
Push-pull outputs, both polarities
The TPS3305-33DR provides both active-high and active-low reset outputs in a push-pull, totem-pole configuration. No external pull-up resistor is needed on either output. The active-high output can directly enable a power-good LED or a logic gate; the active-low output connects directly to the /RESET pin of most MCUs and FPGAs.
8-SOIC footprint, industrial temperature
Packaged in an 8-SOIC (3.90 mm width) body, surface-mount. The junction temperature rating (TJ) matches the ambient range — no derating needed for typical use at 85°C ambient.
For new designs, this means no near-term supply discontinuity; for existing BOMs, it is safe to continue specifying without an imminent obsolescence watch.