MB3773 Fujitsu, MB3773 Datasheet - Page 21

• Manufacturer Part Number: MB3773
• Description: Power Supply Monitor with Watch-Dog Timer
• Manufacturer: Fujitsu

C
T
CK waveform
C
2
voltage
• This is an example application to limit upper frequency f
• When a clock pulse such as shown below is sent to pin CK, a short T
T
1
microcomputer.
If the CK cycle sent from the microcomputer exceeds f
signal.
(The lower freqency has already been set using Cr.)
from reaching the CK input threshold level ( 1.25V), and will cause a reset signal to be
output.
The T
0.3 C
Example : Setting C and R allow the upper T
1
EXAMPLE 11 : Circuit for Limiting Upper Clock Input Frequency
2
R
value can be found using the following formula :
2
T
1
2
3
4
3
0.01 F
0.1 F
C
T
2
T
1
8
7
6
5
C
where V
2
10k
10k
R
R
2
CC
1
T
r1
value to be set (See the table below.)
= 5V, T
R
1
=10k
H
H
3
, the circuit generates a reset
of clock pulses sent from the
3.0 sec, T
300 s
30 s
RESET
RESET
T
CK
2
1
prevents C
GND
2
20 sec
2
voltage
MB3773
V
CC
(5V)
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