MB3773 Datasheet, PDF (21/29 Pages) Fujitsu Component Limited. – Power Supply Monitor with Watch-Dog Timer

MB3773
VCC( = 5 V)
CT
EXAMPLE 9: Reducing Reset Hold Time
VCC ( = 5 V)
MB3773
1
8
2
7
3
6
4
5
Logic circuit
RESET
RESET
CK
CT
GND
MB3773
1
8
2
7
3
6
4
5
Logic circuit
RESET
RESET
CK
GND
(a) TPR reduction method
(b) Standard usage
Notes : • RESET is the only output that can be used.
• Standard TPR, TWD and TWR value can be found using the following formulas.
Formulas: TPR (ms) =: 100 × CT (µF)
TWD (ms) =: 100 × CT (µF)
TWR (ms) =: 16 × CT (µF)
• The above formulas become standard values in determining TPR, TWD and TWR.
Reset hold time is compared below between the reduction circuit and the standard circuit.
CT = 0.1 µF
TPR =:
TWD =:
TWR =:
TPR reduction circuit
10 ms
10 ms
1.6 ms
Standard circuit
100 ms
10 ms
2.0 ms
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