MC74HC4020A ON Semiconductor, MC74HC4020A Datasheet - Page 7

• Manufacturer Part Number: MC74HC4020A
• Description: 14-Stage Binary Ripple Counter High-Performance Silicon-Gate CMOS
• Manufacturer: ON Semiconductor

Time−Base Generator
connected directly to a standard 120 Vac power line is
applied to the input of the MC54/74HC14A, Schmitt-trigger
inverter. The HC14A squares−up the input waveform and
120Vac
Reset
A 60Hz sinewave obtained through a 1.0 Megohm resistor
Clock
60Hz
Q10
Q12
Q13
Q14
Q4
Q5
Q6
Q7
Q8
Q9
NOTE:
Ground MUST be isolated
by a transformer or
opto−isolator for safety
reasons.
1
2
1.0M
≥20pF
4
8
V
CC
16
1/6 of HC14A
APPLICATIONS INFORMATION
Figure 8. Timing Diagram
32
Figure 9. Time−Base Generator
http://onsemi.com
MC74HC4020A
64
Clock
HC4020A
7
V
128
CC
feeds the HC4020A. Selecting outputs Q5, Q10, Q11, and
Q12 causes a reset every 3600 clocks. The HC20 decodes the
counter outputs, produces a single (narrow) output pulse,
and resets the binary counter. The resulting output frequency
is 1.0 pulse/minute.
Q10
Q11
Q12
Q5
256
13
12
10
9
512
HC20
1/2
1024
8
2048
1
2
4
5
HC20
4096
1/2
6
8192
1.0 Pulse/Minute
Output
16384