FUJITSU SEMICONDUCTOR
DATA SHEET
DS04-27402-2E
ASSP
POWER-VOLTAGE MONITORING
IC WITH WATCHDOG TIMER
MB3793-
42/30
DESCRIPTION
The MB3793 is an integrated circuit to monitor power voltage; it incorporates a watchdog
timer.
A reset signal is output when the power is cut or falls abruptly. When the power recovers
normally after resetting, a power-on reset signal is output to microprocessor units (MPUs).
An internal watchdog timer with two inputs for system operation diagnosis can provide a
fail-safe function for various application systems.
Two models with detection voltages of 4.2 and 3.0 V are available. There is also a mask
option that can detect voltages of 4.9 to 3.0 V in 0.1-V steps.
The model numbers are MB3793-42 or -30 corresponding to the detected voltage. The
model number and package code are as shown below.
8-PIN PLASTIC DIP
(DIP-8P-M01)
Model No.
MB3793-42
MB3793-30
Package code
3793-A
3793-N
Detection voltage
4.2 V
3.0 V
8-PIN PLASTIC SOL
(FPT-8P-M02)
FEATURES
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Precise detection of power voltage fall:
±2.5%
Detection voltage with hysteresis
Low power dispersion: ICC = 27
µA
(reference)
Internal dual-input watchdog timer
Watchdog-timer halt function (by inhibition pin)
Independently-set watchdog and reset times
Mask option for detection voltage (4.9 to 3.0 V, 0.1-V steps)
This device contains circuitry to protect the inputs against
damage due to high static voltages or electric fields. However,
it is advised that normal precautions be taken to avoid
application of any voltage higher than maximum rated voltages
to this high impedance circuit.
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