TC1232
Microprocessor Monitor
Features: General Description: Precision Voltage Monitor:
-Adjustable +4.5V or +4.75V Reset Pulse Width – 250 ms minimum No External Components Adjustable Watchdog Timer:
-150 ms, 600 ms or 1.2s Operating Voltage 4.0V to 5.5V Debounced Manual Reset Input for External
Override The TC1232 is a fully-integrated processor supervisor
that provides three important functions to safeguard
processor sanity: precision power on/off Reset control,
Watchdog Timer and external Reset override.
On power-up, the TC1232 holds the processor in the
Reset state for a minimum of 250 ms after VCC is within
tolerance to ensure a stable system start-up.
Microprocessor sanity is monitored by the on-board
watchdog circuit. The microprocessor must provide a
periodic low-going signal on the ST input. Should the
processor fail to supply this signal within the selected
time-out period (150 ms, 600 ms or 1200 ms), an outof-control processor is indicated and the TC1232
issues a processor Reset as a result. Block Diagram
VCC
RST Tolerance
Select
(5% or 10%) TOL +
– + …