NJM2078 查看數據表（PDF） - Japan Radio Corporation

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产品描述 (功能)

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NJM2078

VOLTAGE DETECTOR

Japan Radio Corporation  

NJM2078

3. Detection of Abnormal Operating Voltage

4. Programmable Zener

V+H

=

1 +

R3

R4

 VR

V

+

L

=

1 +

R1

R2

 VR

Note : V+L≥2.5V

VZ･=･ 1

+

R2

R3



VR

Vz ≤V V + − Vz ≤6mA

R2 + R3

R1

Can use channel B independently.

5. Reset Circuit for Decreased Operating Voltage

Comparate Voltage and hysterisis width can be

adjustabel by R1 to R4. Roughly.

V +(L)

=

R1

+ R2

R3

+ R3

VTH

V

+

(H)

=

V

+

(L)

R1(R2 + R3 )

R 3R 4

VTH

● Power-on reset time tRST (roughly)

tRST = -C1R4 In

1 −

VTH

V+

1 +

R1

R2 + R3



● Transistor ; Recommended hFE = 50 to 200

● Rapid Signal Off ; Be care to remained charge

of C1. It affects to tRST

● Reverse polarity output OUT : Open collector.

-6-

Ver.2003-12-09

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