The TPS3420, TPS3421, and TPS3422 (TPS342x) are low-current,
ultrasmall, push-button reset timers. These devices use a long timing setup delay to provide the
intended system reset, and avoid resets from short push-button closures or key presses. This reset
configuration also allows for differentiation between software interrupts and hard system
The TPS3420 and TPS3421 monitor two inputs (PB1 and PB2) and output an active-low reset
pulse signal (RST) when both inputs are low for the selected time delay. For
the TPS3421, RST remains low for a factory-programmed fixed time. For the
TPS3420, RST remains low until one of the PBx inputs is released. The need
for a dedicated reset button is eliminated because two inputs are used to ensure reset. The TPS3422
monitors one input (PB1) and outputs an active-low reset pulse signal (RST)
when PB1 is low for the selected time delay.
The TPS342x have an open-drain output that can be wire-ORed with other open-drain
devices. The TPS342x operate from 1.6 V to 6.5 V over the 40°C to +125°C temperature range, and
provide a precise, space-conscious micropower solution for system resetting needs.