5-387
FAST AND LS TTL DATA
OCTAL BUFFER/LINE DRIVER
WITH 3-STATE OUTPUTS
The SN54/74LS240, 241 and 244 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.
•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
LOGIC AND CONNECTION DIAGRAMS DIP (TOP VIEW)
18 17 16 15 14 13
1 2 3 4 5 6 7
20 19
8
VCC
1G
2G 1Y1 2A4 1Y2 1Y32A3 2A2
1A1 2Y4 1A2 2Y3 1A3 2Y2 1A4
9 10
2Y1 GND
12 11
1Y4 2A1
18 17 16 15 14 13
1 2 3 4 5 6 7
20 19
8
VCC
1G
2G 1Y1 2A4 1Y2 1Y32A3 2A2
1A1 2Y4 1A2 2Y3 1A3 2Y2 1A4
9 10
2Y1 GND
12 11
1Y4 2A1
18 17 16 15 14 13
1 2 3 4 5 6 7
20 19
8
VCC
1G
2G 1Y1 2A4 1Y2 1Y32A3 2A2
1A1 2Y4 1A2 2Y3 1A3 2Y2 1A4
9 10
2Y1 GND
12 11
1Y4 2A1
SN54/74LS240
SN54/74LS241
SN54/74LS244
SN54/74LS240
SN54/74LS241
SN54/74LS244
OCTAL BUFFER/LINE DRIVER
WITH 3-STATE OUTPUTS
LOW POWER SCHOTTKY
ORDERING INFORMATION
SN54LSXXXJ Ceramic
SN74LSXXXN Plastic
SN74LSXXXDW SOIC
20
1
J SUFFIX
CERAMIC
CASE 732-03
20 1
N SUFFIX
PLASTIC
CASE 738-03
20
1
DW SUFFIX
SOIC
CASE 751D-03
5-388
FAST AND LS TTL DATA
SN54/74LS240 • SN54/74LS241 • SN54/74LS244
TRUTH TABLES
SN54/74LS240
INPUTS
OUTPUT
1G, 2G D
OUTPUT
L
L
H
L
H
X
H
L
(Z)
SN54/74LS244
INPUTS
OUTPUT
1G, 2G D
OUTPUT
L
L
H
L
H
X
L
H
(Z)
SN54/74LS241
INPUTS
OUTPUT
INPUTS
OUTPUT
1G D
OUTPUT
2G D
OUTPUT
L
L
H
L
H
X
L
H
(Z)
H
H
L
L
H
X
L
H
(Z)
H = HIGH Voltage Level
L = LOW Voltage Level
X = Immaterial
Z = HIGH Impedance
GUARANTEED OPERATING RANGES
Symbol Parameter Min Typ Max Unit
VCC Supply Voltage 54
74 4.5
4.75 5.0
5.0 5.5
5.25 V
TAOperating Ambient Temperature Range 54
74 –55
025
25 125
70 °C
IOH Output Current — High
54, 74 –3.0 mA
OH
54
74 –12
–15 mA
IOL Output Current — Low 54
74 12
24 mA
5-389
FAST AND LS TTL DATA
SN54/74LS240 • SN54/74LS241 • SN54/74LS244
DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE (unless otherwise specified)
Symbol
Parameter
Limits
Unit
Test Conditions
Symbol
Parameter
Min Typ Max
Unit
Test Conditions
VIH Input HIGH Voltage 2.0 V Guaranteed Input HIGH Voltage for
All Inputs
VIL
Input LOW Voltage
54 0.7
V
Guaranteed Input LOW Voltage for
All Inputs
VIL
Input LOW Voltage
74 0.8
V
Guaranteed Input LOW Voltage for
All Inputs
VT+–VT– Hysteresis 0.2 0.4 V VCC = MIN
VIK Input Clamp Diode Voltage –0.65 –1.5 V VCC = MIN, IIN = –18 mA
VOH
Output HIGH Voltage
54, 74 2.4 3.4 V VCC = MIN, IOH = –3.0 mA
VOH
Output HIGH Voltage
54, 74 2.0 V VCC = MIN, IOH = MAX
VOL
Output LOW Voltage
54, 74 0.25 0.4 V IOL = 12 mA
VCC = VCC MIN,
VIN = VIL or VIH
per Truth Table
VOL
Output LOW Voltage
74 0.35 0.5 V IOL = 24 mA
VIN = VIL or VIH
per Truth Table
IOZH Output Off Current HIGH 20 µA VCC = MAX, VOUT = 2.7 V
IOZL Output Off Current LOW –20 µA VCC = MAX, VOUT = 0.4 V
IIH
Input HIGH Current
20 µA VCC = MAX, VIN = 2.7 V
IIH
Input HIGH Current
0.1 mA VCC = MAX, VIN = 7.0 V
IIL Input LOW Current –0.2 mA VCC = MAX, VIN = 0.4 V
IOS Output Short Circuit Current (Note 1) –40 –225 mA VCC = MAX
ICC
Power Supply Current
Total, Output HIGH 27
mA
VCC = MAX
ICC
Total, Output LOW LS240 44
mA
VCC = MAX
ICC
LS241/244 46
mA
VCC = MAX
Total at HIGH Z LS240 50
LS241/244 54
Note 1: Not more than one output should be shorted at a time, nor for more than 1 second.
AC CHARACTERISTICS (TA = 25°C, VCC = 5.0 V)
Symbol
Parameter
Limits
Unit
Test Conditions
Symbol
Parameter
Min Typ Max
Unit
Test Conditions
tPLH
tPHL Propagation Delay, Data to Output
LS240 9.0
12 14
18 ns
CL = 45 pF,
RL = 667 Ω
tPLH
tPHL Propagation Delay, Data to Output
LS241/244 12
12 18
18 ns
CL = 45 pF,
RL = 667 Ω
tPZH Output Enable Time to HIGH Level 15 23 ns
L = 667 Ω
tPZL Output Enable Time to LOW Level 20 30 ns
tPLZ Output Disable Time from LOW Level 15 25 ns
C
L = 5.0 pF,
RL = 667 Ω
tPHZ Output Disable Time from HIGH Level 10 18 ns
CL = 5.0 pF,
RL = 667 Ω
AC WAVEFORMS
Ω
≥
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
≈
≈
SWITCH POSITIONS
5-390
FAST AND LS TTL DATA
SN54/74LS240 • SN54/74LS241 • SN54/74LS244
5-391
FAST AND LS TTL DATA
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! " !
&
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! " #
" #!
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-A-
-B- P
110
1120
G
-T-
D
K
C
R X 45°
MFJ
Case 751D-03 DW Suffix
20-Pin Plastic
SO-20 (WIDE)
"
! !
Case 732-03 J Suffix
20-Pin Ceramic Dual In-Line
"!
! $" '' " #
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°
°
!
!
!
!
°
°
B
C
DG
H
J
M
N
AL
20 11
1 10
K
F
Case 738-03 N Suffix
20-Pin Plastic
°
°
!
!
!
!
!
!
°
°
"!
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&
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! ( " " $
! ( ! " #
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-A-
B
C
K
NE
G F D
J
L
M
-T-
1 10
1120
" "
5-392
FAST AND LS TTL DATA
SYMBOL SW1 SW2
tPZH Open Closed
tPZL Closed Open
tPLZ Closed Closed
tPHZ Closed Closed
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the suitability of its products for any particular purpose, nor does Motorola assume any liability arising out of the application or use of any product or circuit,
and specifically disclaims any and all liability , including without limitation consequential or incidental damages. “Typical” parameters can and do vary in different
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associated with such unintended or unauthorized use, even if such claim alleges that Motorola was negligent regarding the design or manufacture of the part.
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