DM74LS90 Decade and Binary Counters
August 1986
Revised March 2000
DM74LS90
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 DM74LS90.
All of these counters have a gated zero reset and the
DM74LS90 also has gated set-to-nine inputs for use in
BCD nine’s complement applications.
To use their maximum count length (decade or four bit
binary), 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 symmetri-
cal divide-by-ten count can be obtained from the
DM74LS90 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
s
Typical power dissipation 45 mW
s
Count frequency 42 MHz
Ordering Code:
Order Number
DM74LS90M
DM74LS90N
Package Number
M14A
N14A
Package Description
14-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-120, 0.150 Narrow
14-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
Connection Diagram
Reset/Count Truth Table
Reset Inputs
R0(1)
H
H
X
X
L
L
X
R0(2)
H
H
X
L
X
X
L
R9(1)
L
X
H
X
L
X
L
R9(2)
X
L
H
L
X
L
X
Q
D
L
L
H
Output
Q
C
L
L
L
Q
B
L
L
L
Q
A
L
L
H
COUNT
COUNT
COUNT
COUNT
© 2000 Fairchild Semiconductor Corporation
DS006381
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DM74LS90
Function Tables
BCD Count Sequence
(Note 1)
Count
Q
D
0
1
2
3
4
5
6
7
8
9
L
L
L
L
L
L
L
L
H
H
Q
C
L
L
L
L
H
H
H
H
L
L
Output
Q
B
L
L
H
H
L
L
H
H
L
L
Q
A
L
H
L
H
L
H
L
H
L
H
Logic Diagram
Bi-Quinary (5-2)
(Note 2)
Count
Q
A
0
1
2
3
4
5
6
7
8
9
H
=
HIGH Level
L
=
LOW Level
X
=
Don’t Care
Note 1:
Output Q
A
is connected to input B for BCD count.
Note 2:
Output Q
D
is connected to input A for bi-quinary count.
Note 3:
Output Q
A
is connected to input B.
The J and K inputs shown without connection are for reference only and
are functionally at a high level.
Output
Q
D
L
L
L
L
H
L
L
L
L
H
Q
C
L
L
H
H
L
L
L
H
H
L
Q
B
L
H
L
H
L
L
H
L
H
L
L
L
L
L
L
H
H
H
H
H
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2
DM74LS90
Absolute Maximum Ratings
(Note 4)
Supply Voltage
Input Voltage (Reset)
Input Voltage (A or B)
Operating Free Air Temperature Range
Storage Temperature Range
7V
7V
5.5V
0°C to
+70°C
−65°C
to
+150°C
Note 4:
The “Absolute Maximum Ratings” are those values beyond which
the safety of the device cannot be guaranteed. The device should not be
operated at these limits. The parametric values defined in the “Electrical
Characteristics” table are not guaranteed at the absolute maximum ratings.
The “Recommended Operating Conditions” table will define the conditions
for actual device operation.
Recommended Operating Conditions
Symbol
V
CC
V
IH
V
IL
I
OH
I
OL
f
CLK
f
CLK
t
W
Supply Voltage
HIGH Level Input Voltage
LOW Level Input Voltage
HIGH Level Output Current
LOW Level Output Current
Clock Frequency (Note 5)
Clock Frequency (Note 6)
Pulse Width (Note 5)
A to Q
A
B to Q
B
A to Q
A
B to Q
B
A
B
Reset
t
W
Pulse Width (Note 6)
A
B
Reset
t
REL
t
REL
T
A
Reset Release Time (Note 5)
Reset Release Time (Note 6)
Free Air Operating Temperature
0
0
0
0
15
30
15
25
50
25
25
35
0
70
ns
ns
°C
ns
ns
Parameter
Min
4.75
2
0.8
−0.4
8
32
16
20
10
MHz
Nom
5
Max
5.25
Units
V
V
V
mA
mA
MHz
Note 5:
C
L
=
15 pF, R
L
=
2 kΩ, T
A
=
25°C and V
CC
=
5V.
Note 6:
C
L
=
50 pF, R
L
=
2 kΩ, T
A
=
25°C and V
CC
=
5V.
Electrical Characteristics
over recommended operating free air temperature range (unless otherwise noted)
Symbol
V
I
V
OH
V
OL
Parameter
Input Clamp Voltage
HIGH Level
Output Voltage
LOW Level
Output Voltage
I
I
Input Current @ Max
Input Voltage
I
IH
HIGH Level
Input Current
I
IL
LOW Level
Input Current
I
OS
I
CC
Short Circuit Output Current
Supply Current
V
CC
=
Max (Note 9)
V
CC
=
Max (Note 7)
V
CC
=
Max, V
I
=
0.4V
Conditions
V
CC
=
Min, I
I
= −18
mA
V
CC
=
Min, I
OH
=
Max
V
IL
=
Max, V
IH
=
Min
V
CC
=
Min, I
OL
=
Max
V
IL
=
Max, V
IH
=
Min
I
OL
=
4 mA, V
CC
=
Min
V
CC
=
Max, V
I
=
7V
V
CC
=
Max
V
I
=
5.5V
V
CC
=
Max, V
I
=
2.7V
Reset
A
B
Reset
A
B
Reset
A
B
−20
9
(Note 8)
2.7
3.4
Min
Typ
(Note 7)
Max
−1.5
Units
V
V
0.35
0.25
0.5
0.4
0.1
0.2
0.4
20
40
80
−0.4
−2.4
−3.2
−100
15
V
mA
µA
mA
mA
mA
Note 7:
All typicals are at V
CC
=
5V, T
A
=
25°C.
3
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DM74LS90
Electrical Characteristics
(Continued)
Note 8:
Q
A
outputs are tested at I
OL
=
Max plus the limit value of I
IL
for the B input. This permits driving the B input while maintaining full fan-out capability.
Note 9:
Not more than one output should be shorted at a time, and the duration should not exceed one second.
Note 10:
I
CC
is measured with all outputs open, both RO inputs grounded following momentary connection to 4.5V and all other inputs grounded.
Switching Characteristics
at V
CC
=
5V and T
A
=
25°C
From (Input)
Symbol
Parameter
To (Output)
A to Q
A
B to Q
B
A to Q
A
A to Q
A
A to Q
D
A to Q
D
B to Q
B
B to Q
B
B to Q
C
B to Q
C
B to Q
D
B to Q
D
SET-9 to Q
A
, Q
D
SET-9 to Q
B
, Q
C
SET-0 to Any Q
C
L
=
15 pF
Min
f
MAX
t
PLH
t
PHL
t
PLH
t
PHL
t
PLH
t
PHL
t
PLH
t
PHL
t
PLH
t
PHL
t
PLH
t
PHL
t
PHL
Maximum Clock
Frequency
Propagation Delay Time
LOW-to-HIGH Level Output
Propagation Delay Time
HIGH-to-LOW Level Output
Propagation Delay Time
LOW-to-HIGH Level Output
Propagation Delay Time
HIGH-to-LOW Level Output
Propagation Delay Time
LOW-to-HIGH Level Output
Propagation Delay Time
HIGH-to-LOW Level Output
Propagation Delay Time
LOW-to-HIGH Level Output
Propagation Delay Time
HIGH-to-LOW Level Output
Propagation Delay Time
LOW-to-HIGH Level Output
Propagation Delay Time
HIGH-to-LOW Level Output
Propagation Delay Time
LOW-to-HIGH Level Output
Propagation Delay Time
HIGH-to-LOW Level Output
Propagation Delay Time
HIGH-to-LOW Level Output
32
16
16
18
48
50
16
21
32
35
32
35
30
40
40
Max
R
L
=
2 kΩ
C
L
=
50 pF
Min
20
10
20
24
52
60
23
30
37
44
36
44
35
48
52
Max
MHz
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Units
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4
DM74LS90
Physical Dimensions
inches (millimeters) unless otherwise noted
14-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-120, 0.150 Narrow
Package Number M14A
5
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