FM1233B

Precision monitoring of 3.3V and lower voltage microprocessor systems
V_TH values of 4.62V, 4.38V and 4.12V
Automatic restart of microprocessor after power failure
Reset Timeout Period Choice: Options AC and AD: 140ms (min)/256ms (typ) Option ABA: 17ms (min)/32ms (typ) Available on request: 32ms (typ) and 128ms (typ)
Internal 5k pull-up resistor
Operating Temperature -40°C to +105°C
Monitors external pushbutton override
Internal switch debounce circuitry
SOT23-3 package

Voltage on any pin relative to GND
V_{CC..............................................................}-0.3V to +6.0V
RESET............................................... .-0.3V to (V_CC+ 0.3V)
Input Current ...........................................................20mA
Output Current (RESET)........................................... 20mA

Continuous Power Dissipation (T_A= 70°C)
SOT23 (derate 4mW above 70°C)....................... 300mW
Operating Temperature Range........... .-40°C to +105°C
Storage Temperature Range.............. .-65°C to +150°C
Lead Temperature (soldering, 10s) .....................+300°C

The FM1233B 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. FM1233B 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 FM1233B is of open-drain active low type.

The FM1233B 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 FM1233B