MB3773 View Datasheet(PDF) - Fujitsu

Part Name

Description

Manufacturer

MB3773

Power Supply Monitor with Watch-Dog Timer

Fujitsu 

MB3773

EXAMPLE 5: Monitoring Two Supply Voltages (with hysteresis and reset output)

VCC2 (12 V)

VCC1 (5 V)

CT

MB3773

1

8

2

7

3

6

4

5

1.2 kΩ

R1

20 kΩ

R6

30 kΩ

R3

Diode

180 kΩ

R4

+

_

Comp. 1

+

_

Comp. 2

5.1 kΩ

R2

4.7 kΩ

R5

Logic circuit

RESET

RESET

CK

GND

Example : Comp. 1, Comp. 2

: MB4204, MB47393

Notes : • When either 5 V or 12 V supply voltage decreases below its detection voltage (VSL),

the MB3773 RESET terminal is set to High and the MB3773 RESET terminal is set to Low.

• Use VCC1 ( = 5 V) to power the comparators (Comp. 1 and Comp. 2) in the external circuit shown

above.

• The detection voltage of the VCC2 ( = 12 V) supply voltage is approximately 9.2 V/9.4 V and has a

hysteresis width of approximately 0.2 V. For the formulas for finding hysteresis width and detection

voltage, refer to section 4.

16

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