
TL/F/6533
D
D
July 1992
DM5490/DM7490A, DM7493A
Decade and Binary Counters
General Description
Each of these monolithic counters contains four master-
slave flip-flops and additional gating to provide a divide-by-
two counter and a three-stage binary counter for which the
count cycle length is divide-by-five for the 90A and divide-
by-eight for the 93A.
All of these counters have a gated zero reset and the 90A
also has gated set-to-nine inputs for use in BCD nine’s com-
plement applications.
To use their maximum count length (decade or four-bit bina-
ry), the B input is connected to the Q
A
output. The input
count pulses are applied to input A and the outputs are as
described in the appropriate truth table. A symmetrical di-
vide-by-ten count can be obtained from the 90A counters by
connecting the Q
D
output to the A input and applying the
input count to the B input which gives a divide-by-ten square
wave at output Q
A
.
Features
Y
Typical power dissipation
D 90A
145 mW
D 93A
130 mW
Y
Count frequency 42 MHz
Connection Diagrams
Dual-In-Line Package
TL/F/6533–1
Order Number DM5490J, DM5490W or DM7490AN
See NS Package Number J14A, N14A or W14B
Dual-In-Line Package
TL/F/6533–2
Order Number DM7493AN
See NS Package Number N14A
C
1995 National Semiconductor Corporation
RRD-B30M105/Printed in U. S. A.