FM1233E Datasheet, PDF (1/7 Pages) Fairchild Semiconductor – 3-Pin μC Supervisor Circuit

February 2003
FM1233E
3-Pin µC Supervisor Circuit
General Description
The FM1233E is a supervisor circuit that monitors a micropro-
cessor power supply or other system voltage and issues a reset
pulse when a fault condition exists. Several different threshold
voltages are offered to accommodate 3V systems with different
tolerances.
The device features a precision temperature-compensated volt-
age reference and comparator. When V_CC falls 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 for
approximately 250 ms to allow the system clock and other cir-
cuits to stabilize. The reset output of FM1233E is of open-drain
active low type.
Features
s Precision monitoring of 3.3V and lower voltage
microprocessor systems
s V_TH values of 2.88V, 2.72V
s Automatic restart of microprocessor after power failure
s 140ms (min) power-on RESET delay (typ.: 256ms)
s Internal 5kΩ pull-up resistor
s Other reset choices available: 32 to 128ms
s Operating Temperature -40°C to +105°C
s SOT23-3 package
Typical Operating Circuit
V_CC
GND
Connection Diagram
3
FM1233E
1
2
RESET
Controller
GND 1
FM1233E 3 V_CC
RESET 2
SOT23-3 Package
©2003 Fairchild Semiconductor Corporation
1
FM1233E Rev. D
www.fairchildsemi.com