The open-drain output lets you pull up to any voltage up to the absolute maximum, so it interfaces directly with 1.8V, 2.5V, 3.3V, or 5V logic without a level shifter.
Open-drain output — wiring and pull-up
Because the output is open drain, the reset signal is high-impedance when the monitored rail is above threshold. You supply the pull-up resistor externally, which means the reset voltage is whatever your pull-up rail is — handy for mixed-voltage boards. The active-low polarity means the reset line goes low when the 1.2V rail droops, and releases high when it recovers. No manual-reset pin on this variant; it's automatic-only, so the processor comes out of reset as soon as the supply is valid.
TSOT-23-6 package — footprint and thermal
The TPS3702CX12DDCT comes in a thin SOT-23-6 (TSOT-23-6) package, surface-mount only. The thin profile suits height-constrained assemblies like PCIe cards or portable instruments. With only one monitored channel and low quiescent current typical of this family, self-heating is negligible — the junction temperature rating of 125°C is driven by ambient, not dissipation. Keep the pull-up resistor value high enough (10 kΩ to 100 kΩ typical) to avoid wasting current when the output is low.