SN74LS240, SN74LS244
Octal Buffer/Line Driver
with 3−State Outputs
The SN74LS240 and SN74LS244 are Octal Buffers and Line
Drivers designed to be employed as memory address drivers, clock
drivers and bus-oriented transmitters/receivers which provide
improved PC board density.
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•
Hysteresis at Inputs to Improve Noise Margins
•
3-State Outputs Drive Bus Lines or Buffer Memory Address
Registers
•
Input Clamp Diodes Limit High-Speed Termination Effects
GUARANTEED OPERATING RANGES
Symbol
V
CC
T
A
I
OH
I
OL
Parameter
Supply Voltage
Operating Ambient
Temperature Range
Output Current
−
High
Min
4.75
0
Typ
5.0
25
Max
5.25
70
−3.0
−15
Output Current
−
Low
24
Unit
V
°C
mA
mA
mA
20
1
LOW
POWER
SCHOTTKY
MARKING
DIAGRAMS
SN74LS24xN
AWLYYWW
1
PDIP−20
N SUFFIX
CASE 738
20
1
LS24x
AWLYYWW
SOIC−20
DW SUFFIX
CASE 751D
1
20
1
74LS24x
AWLYWW
SOEIAJ−20
M SUFFIX
CASE 967
x
A
WL
YY
WW
1
= 0 or 4
= Assembly Location
= Wafer Lot
= Year
= Work Week
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 5 of this data sheet.
©
Semiconductor Components Industries, LLC, 2006
July, 2006
−
Rev. 9
1
Publication Order Number:
SN74LS240/D
SN74LS240, SN74LS244
LOGIC AND CONNECTION DIAGRAMS DIP
(TOP VIEW)
SN74LS240
V
CC
20
2G
19
1Y1
18
2A4 1Y2 2A3 1Y3 2A2 1Y4 2A1
17
16
15
14
13
12
11
1
1G
2
1A1
3
4
5
2Y4 1A2 2Y3
8
9
10
6
7
1A3 2Y2 1A4 2Y1 GND
SN74LS244
V
CC
20
2G
19
1Y1
18
2A4 1Y2 2A3 1Y3 2A2 1Y4 2A1
17
16
15
14
13
12
11
1
1G
2
1A1
3
4
5
2Y4 1A2 2Y3
8
9
10
6
7
1A3 2Y2 1A4 2Y1 GND
TRUTH TABLES
SN74LS240
INPUTS
1G, 2G
L
L
H
D
L
H
X
OUTPUT
H
L
(Z)
H = HIGH Voltage Level
L = LOW Voltage Level
X = Immaterial
Z = HIGH Impedance
SN74LS244
INPUTS
1G, 2G
L
L
H
D
L
H
X
OUTPUT
L
H
(Z)
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2
SN74LS240, SN74LS244
DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE
(unless otherwise specified)
Limits
Symbol
V
IH
V
IL
V
T+
−V
T−
V
IK
V
OH
Parameter
Input HIGH Voltage
Input LOW Voltage
Hysteresis
Input Clamp Diode Voltage
Output HIGH Voltage
2.4
2.0
0.25
0.35
0.4
0.5
20
−20
20
0.1
−0.2
−40
−225
27
LS240
LS244
Total at HIGH Z
LS240
44
46
50
mA
V
CC
= MAX
0.2
0.4
−0.65
3.4
−1.5
Min
2.0
0.8
Typ
Max
Unit
V
V
V
V
V
V
V
V
μA
μA
μA
mA
mA
mA
Test Conditions
Guaranteed Input HIGH Voltage for
All Inputs
Guaranteed Input LOW Voltage for
All Inputs
V
CC
= MIN
V
CC
= MIN, I
IN
=
−
18 mA
V
CC
= MIN, I
OH
=
−
3.0 mA
V
CC
= MIN, I
OH
= MAX
I
OL
= 12 mA
I
OL
= 24 mA
V
CC
= V
CC
MIN,
V
IN
= V
IL
or V
IH
per Truth Table
V
OL
I
OZH
I
OZL
I
IH
I
IL
I
OS
Output LOW Voltage
Output Off Current HIGH
Output Off Current LOW
Input HIGH Current
Input LOW Current
Output Short Circuit Current (Note 1)
Power Supply Current
Total, Output HIGH
Total, Output LOW
V
CC
= MAX, V
OUT
= 2.7 V
V
CC
= MAX, V
OUT
= 0.4 V
V
CC
= MAX, V
IN
= 2.7 V
V
CC
= MAX, V
IN
= 7.0 V
V
CC
= MAX, V
IN
= 0.4 V
V
CC
= MAX
I
CC
LS244
54
1. Not more than one output should be shorted at a time, nor for more than 1 second.
AC CHARACTERISTICS
(T
A
= 25°C, V
CC
= 5.0 V)
Limits
Symbol
t
PLH
t
PHL
t
PLH
t
PHL
t
PZH
t
PZL
t
PLZ
t
PHZ
Parameter
Propagation Delay, Data to Output
LS240
Propagation Delay, Data to Output
LS244
Output Enable Time to HIGH Level
Output Enable Time to LOW Level
Output Disable Time from LOW Level
Output Disable Time from HIGH Level
Min
Typ
9.0
12
12
12
15
20
15
10
Max
14
18
18
18
23
30
25
18
Unit
ns
ns
ns
ns
ns
ns
C
L
= 5.0 pF,
R
L
= 667
Ω
C
L
= 45 pF,
R
L
= 667
Ω
Test Conditions
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3
SN74LS240, SN74LS244
AC WAVEFORMS
V
IN
1.3 V
t
PLH
1.3 V
t
PHL
1.3 V
V
CC
R
L
SW1
TO OUTPUT
UNDER TEST
V
OUT
1.3 V
Figure 1.
V
IN
1.3 V
t
PHL
1.3 V
t
PLH
1.3 V
C
L
*
5 kΩ
SW2
V
OUT
1.3 V
Figure 2.
V
E
V
E
V
OUT
1.3 V
t
PZL
1.3 V
1.3 V
t
PLZ
≈
1.3 V
V
OL
SWITCH POSITIONS
SYMBOL
t
PZH
t
PZL
t
PLZ
t
PHZ
SW1
Open
Closed
Closed
Closed
SW2
Closed
Open
Closed
Closed
0.5 V
Figure 3.
Figure 5.
V
E
V
E
V
OUT
1.3 V
t
PZH
1.3 V
1.3 V
t
PHZ
≥V
OH
≈
1.3 V
0.5 V
Figure 4.
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4
SN74LS240, SN74LS244
DEVICE ORDERING INFORMATION
Device Order Number
SN74LS240N
SN74LS240DW
SN74LS240DWR2
SN74LS240M
SN74LS240MEL
SN74LS244N
SN74LS244DW
SN74LS244DWR2
SN74LS244M
SN74LS244MEL
Package Type
PDIP−20
SOIC−WIDE
SOIC−WIDE
SOEIAJ−20
SOEIAJ−20
PDIP−20
SOIC−WIDE
SOIC−WIDE
SOEIAJ−20
SOEIAJ−20
Tape and Reel Size
1440 Units/Box
38 Units/Rail
2500/Tape and Reel
See Note 2
See Note 2
1440 Units/Box
38 Units/Rail
2500/Tape and Reel
See Note 2
See Note 2
2. For ordering information on the EIAJ version of the SOIC package, please contact your local ON Semiconductor representative.
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5
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