FM1233A

The FM1233A is a supervisor circuit that monitors a microprocessor power supply or other system voltage and issues a reset pulse when a fault condition exists. Several different threshold
voltages are offered to accommodate 3.3V and 3.0V systems with different tolerances. FM1233A features a precision temperature-compensated voltage reference and comparator. When V_CCfalls to the threshold voltage, a RESET pulse is issued, holding the output in the active state. When power rises above V_TH, the reset remains asserted for a minimum period (tRST) to allow the system clock and other circuits to stabilize. The reset output of FM1233A is of open-drain active low type.

The FM1233A also can monitor a switch closure on its output, enabling it to recognize an external reset from a pushbutton switch or a P. In the case of a switch, the closure will  be debounced by circuitry internal to the FM1233A.