MC74HC4020A
http://onsemi.com
6
APPLICATIONS INFORMATION
Time−Base Generator
A 60Hz sinewave obtained through a 1.0 Megohm resistor
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
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.
HC4020A
Figure 8. Time−Base Generator
Clock Q5
Q10
Q11
Q12
V
CC
13
12
10
9
1
2
4
5
8
1/2
HC20
1/2
HC20
6
1/6 of HC14A
≥20pF
1.0M
1.0 Pulse/Minute
Output
V
CC
120Vac
60Hz
NOTE: Ground MUST be isolated
by a transformer or
opto−isolator for safety
reasons.
ORDERING INFORMATION
Device Package Shipping
†
MC74HC4020ADG SOIC−16
(Pb−Free)
48 Units / Rail
MC74HC4020ADR2G SOIC−16
(Pb−Free)
2500 / Tape & Reel
MC74HC4020ADTR2G TSSOP−16
(Pb−Free)
2500 / Tape & Reel
NLV74HC4020ADTR2G* TSSOP−16
(Pb−Free)
2500 / Tape & Reel
†For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging
Specifications Brochure, BRD8011/D.
*NLV Prefix for Automotive and Other Applications Requiring Unique Site and Control Change Requirements; AEC−Q100 Qualified and PPAP
Capable.