FUJITSU SEMICONDUCTOR
DATA SHEET
DS04-27400-7E
ASSP For power supply applications
BIPOLAR
Power Supply Monitor
MB3771
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DESCRIPTION
The Fujitsu MB3771 is designed to monitor the voltage level of one or two power supplies (+5 V and an arbitrary
voltage) in a microprocessor circuit, memory board in large-size computer, for example.
If the circuit’s power supply deviates more than a specified amount, then the MB3771 generates a reset signal to
the microprocessor. Thus, the computer data is protected from accidental erasure.
Using the MB3771 requires few external components. To monitor only a +5 V supply, the MB3771 requires the
connection of one external capacitor. The level of an arbitrary detection voltage is determined by two external
resistors. The MB3771 is available in an 8-pin Dual In-Line, Single In-Line Package or space saving Flat Package.
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FEATURES
•
•
•
•
•
•
•
•
•
Precision voltage detection
(V
SA
=
4.2 V
±
2.5
%)
User selectable threshold level with hysterisis (V
SB
= 1.23 V
±
1.5
%)
Monitors the voltage of one or two power supplies (5 V and an arbitrary voltage,
>1.23
V)
Usable as over voltage detector
Low voltage output for reset signal (V
CC
= 0.8 V typ.)
Minimal number of external components (one capacitor min.)
Low power dissipation (I
CC
= 0.35 mA typ., V
CC
= 5 V)
Detection threshold voltage has hysteresis function
Reference voltage is connectable.
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PACKAGES
8-pin plastic DIP
8-pin plastic SIP
8-pin plastic SOIP
(DIP-8P-M01)
(SIP-8P-M03)
(FPT-8P-M01)
FUJITSU [ FUJITSU COMPONENT LIMITED. ]
