X5001 pdf datasheet (CPU Super

This device combines three popular functions, Poweron
Reset, Watchdog Timer, and Supply Voltage
Supervision in one package. This combination lowers
system cost, reduces board space requirements, and
increases reliability.
The watchdog timer provides an independent protection
mechanism for microcontrollers. During a system
failure, the device will respond with a RESET signal
after a selectable time out interval. The user selects the
interval from three preset values. Once selected, the
interval does not change, even after cycling the power.
The user’s system is protected from low voltage conditions
by the device’s low VCC detection circuitry. When
VCC falls below the minimum VCC trip point, the system
is reset. RESET is asserted until VCC returns to proper
operating levels and stabilizes. Five industry standard
VTRIP thresholds are available, however, Intersil’s
unique circuits allow the threshold to be reprogrammed
to meet custom requirements or to fine-tune the threshold
for applications requiring higher precision.
The device utilizes Intersil’s proprietary Direct Write?
cell for the watchdog timer control bits and the VTRIP
storage element, providing a minimum endurance of
100,000 write cycles and a minimum data retention of
100 years.