HD74HC490 Datasheet, PDF (2/8 Pages) Hitachi Semiconductor – Dual 4-bit Decade Counters

HD74HC490
BCD Count Sequence
Outputs
Count
Q_D
Q_C
Q_B
Q_A
0
L
L
L
L
1
L
L
L
H
2
L
L
H
L
3
L
L
H
H
4
L
H
L
L
5
L
H
L
H
6
L
H
H
L
7
L
H
H
H
8
H
L
L
L
9
H
L
L
H
Pin Arrangement
1Clock ₁
1Clear 2
1QA
Output ³
1 Set-
to-9
4
1QB ₅
1QC 6
1QD 7
GND 8
16 VCC
CLR
QA
CK
QB
QC
15 2Clock
CLR
QA
CK
QB
14 2Clear
13 ^2QA
Output
12
2 Set-
to-9
11 2QB
QD
QC
10 2QC
QD
9 2QD
(Top view)
2