MB3773 Datasheet, PDF (22/31 Pages) Fujitsu Component Limited. – Power Supply Monitor with Watch-Dog Timer

MB3773
V_CC(  5
C_T
EXAMPLE 9: Reducing Reset Hold Time
VCC (  5 V)
MB3773
1
8
2
7
3
6
4
5
Logic circuit
RESET
RESET
CK
C_T
GND
MB3773
1
8
2
7
3
6
4
5
Logic circuit
RESET
RESET
CK
GND
(a) T_PR reduction method
(b) Standard usage
Notes :
• RESET is the only output that can be used.
• Standard T_PR, T_WD and T_WR value can be found using the following formulas.
Formulas:T_PR (ms) =: 100 × CT (μF)
T_WD (ms) =: 100 × CT (μF)
T_WR (ms) =: 16 × CT (μF)
• The above formulas become standard values in determining T_PR, T_WD and T_WR.
Reset hold time is compared below between the reduction circuit and the standard circuit.
C_T  0.1 μF
T_PR =:
T_WD =:
T_WR =:
TPR reduction circuit
10 ms
10 ms
1.6 ms
Standard circuit
100 ms
10 ms
2.0 ms
Document Number: 002-08513 Rev. *A
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