HD74LS293 Datasheet, PDF (2/8 Pages) Hitachi Semiconductor – 4-bit Binary Counters

HD74LS293
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
10
H
L
H
L
11
H
L
H
H
12
H
H
L
L
13
H
H
L
H
14
H
H
H
L
15
H
H
H
H
Notes: 1. H; high level, L; low level, X; irrelevant
2. Output Q_A is connected to input B.
Block Diagram
Input A
J
Q
QA
CK
K
Input B
J
Q
QB
CK
K
J
Q
QC
CK
K
R0(1)
R0(2)
J
Q
QD
CK
K
Rev.3.00, Jul.15.2005, page 2 of 7