X40626 pdf datasheet (Dual Vol

The X40626 combines four popular functions, Power-on
Reset Control, Watchdog Timer, Dual Supply Voltage
Supervision, and Serial EEPROM Memory in one package.
This combination lowers system cost, reduces
board space requirements, and increases reliability.
Applying power to the device activates the power-on
reset circuit which holds RESET active for a period of
time. This allows the power supply and oscillator to stabilize
before the processor can execute code.
The Watchdog Timer provides an independent protection
mechanism for microcontrollers. When the microcontroller
fails to restart a timer within a selectable timeout
interval, the device activates the RESET signal. The
user selects the interval from three preset values. Once
selected, the interval does not change, even after cycling
the power.