FUJITSU SEMICONDUCTOR
DATA SHEET
DS04-27401-4E
ASSP
Power Supply Monitor
with Watch-Dog Timer
MB3773
s
DESCRIPTION
The Fujitsu MB3773 is designed to monitor the voltage level of a power supply (+5V or an
arbitrary voltage) in a microprocessor circuit, memory board in a large-size computer, for
example. The MB3773 also contains a watch-dog timer function to detect uncontrol. Table
status of processor and reset system/processor.
If the circuit’s power supply deviates more than a specified amount, then the MB3773
generates a reset signal to the microprocessor. Thus, the computer data is protected from
accidental erasure.
When the MB3773 does not receive the clock pulse from the processor in the specified
period, the MB3773 generates a reset signal to the mciroprocessor.
Using the MB3773 requires few external components. To monitor only a +5 volt supply,
the MB3773 requires the connection of one external capacitor.
The MB3773 is available in an 8-pin Dual In-Line package space saving Flat Package, or
a Single In-Line Package.
•Precision
voltage detection (V
S
= 4.2V
±2.5%)
•Threshold
level with hysterisis
•Low
voltage output for reset signal (V
CC
= 0.8V typ.)
•Precision
reference voltage output (V
REF
= 1.245 V±1.5%)
•External
clock monitor and reset signal generator
•Negative-edge
input watch-dog timer
•Minimal
number of external components (one capacitor min.)
•Available
in a variety of packages
•
8-pin Dual In-Line Package
•
8-pin Flat Package
•
8-pin Single In-Line Package
PLASTIC PACKAGE
SIP-8P-M03
PLASTIC PACKAGE
FPT-8P-M01
PLASTIC PACKAGE
DIP-8P-M01
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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FUJITSU [ FUJITSU COMPONENT LIMITED. ]
