DS04-27401-7E
FUJITSU SEMICONDUCTOR
DATA SHEET
ASSP
Power Supply Monitor
with Watch-Dog Timer
MB3773
■
DESCRIPTION
MB3773 generates the reset signal to protect an arbitrary system when the power-supply voltage momentarily is
intercepted or decreased. It is IC for the power-supply voltage watch and “Power on reset” is generated at the
normal return of the power supply. MB3773 sends the microprocessor the reset signal when decreasing more
than the voltage, which the power supply of the system specified, and the computer data is protected from an
accidental deletion.
In addition, the watchdog timer for the operation diagnosis of the system is built into, and various microprocessor
systems can provide the fail-safe function. If MB3773 does not receive the clock pulse from the processor for an
specified period, MB3773 generates the reset signal.
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FEATURES
• Precision voltage detection (V
S
= 4.2 V
±
2.5 %)
• Detection threshold voltage has hysteresis function
• Low voltage output for reset signal (V
CC
= 0.8 V Typ)
• Precision reference voltage output (V
R
= 1.245 V
±
1.5%)
• With built-in watchdog timer of edge trigger input.
• External parts are few.(1 piece in capacity)
• The reset signal outputs the positive and negative both theories reason.
■
PACKAGES
(DIP-8P-M01)
(FPT-8P-M01)
(SIP-8P-M03)
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.
