![](http://datasheet.mmic.net.cn/280000/74LS90_datasheet_16048219/74LS90_2.png)
Absolute Maximum Ratings
(Note)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales
Office/Distributors for availability and specifications.
Supply Voltage
7V
Input Voltage (Reset)
7V
Input Voltage (A or B)
5.5V
Operating Free Air Temperature Range
DM74LS
0
§
C to
a
70
§
C
b
65
§
C to
a
150
§
C
Storage Temperature Range
Note: The ‘‘Absolute Maximum Ratings’’ are those values
beyond which the safety of the device cannot be guaran-
teed. 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
Parameter
DM74LS90
Units
Min
Nom
Max
V
CC
Supply Voltage
4.75
5
5.25
V
V
IH
High Level Input Voltage
2
V
V
IL
Low Level Input Voltage
0.8
V
I
OH
High Level Output Current
b
0.4
mA
I
OL
Low Level Output Current
8
mA
f
CLK
Clock Frequency (Note 1)
A to Q
A
0
32
MHz
B to Q
B
0
16
f
CLK
Clock Frequency (Note 2)
A to Q
A
0
20
MHz
B to Q
B
0
10
t
W
Pulse Width (Note 1)
A
15
B
30
ns
Reset
15
t
W
Pulse Width (Note 2)
A
25
B
50
ns
Reset
25
t
REL
Reset Release Time (Note 1)
25
ns
t
REL
Reset Release Time (Note 2)
35
ns
§
C
T
A
Free Air Operating Temperature
0
70
Note 1:
C
L
e
15 pF, R
L
e
2 k
X
, T
A
e
25
§
C and V
CC
e
5V.
Note 2:
C
L
e
50 pF, R
L
e
2 k
X
, T
A
e
25
§
C and V
CC
e
5V.
’LS90 Electrical Characteristics
over recommended operating free air temperature range (unless otherwise noted)
Symbol
Parameter
Conditions
Min
Typ
Max
Units
(Note 1)
V
I
Input Clamp Voltage
V
CC
e
Min, I
I
e b
18 mA
V
CC
e
Min, I
OH
e
Max
V
IL
e
Max, V
IH
e
Min
V
CC
e
Min, I
OL
e
Max
V
IL
e
Max, V
IH
e
Min
(Note 4)
b
1.5
V
V
OH
High Level Output
Voltage
2.7
3.4
V
V
OL
Low Level Output
Voltage
0.35
0.5
V
I
OL
e
4 mA, V
CC
e
Min
V
CC
e
Max, V
I
e
7V
V
CC
e
Max
V
I
e
5.5V
0.25
0.4
I
I
Input Current
@
Max
Input Voltage
Reset
0.1
A
0.2
mA
B
0.4
2