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.
SN54/74LS240
SN54/74LS241
SN54/74LS244
OCTAL BUFFER/ LINE DRIVER
WITH 3-STATE OUTPUTS
LOW POWER SCHOTTKY
•
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)
SN54 / 74LS240
VCC 2G
20
19
1Y1
18
2A4 1Y2
17
16
2A3
15
1Y3 2A2 1Y4
14
13
12
2A1
11
20
1
J SUFFIX
CERAMIC
CASE 732-03
20
N SUFFIX
PLASTIC
CASE 738-03
1
1
1G
2
1A1
3
4
5
6
1A3
7
8
9
10
GND
2Y4 1A2 2Y3
2Y2 1A4 2Y1
SN54 / 74LS241
VCC 2G
20
19
1Y1
18
2A4 1Y2
17
16
2A3
15
1Y3 2A2 1Y4
14
13
12
2A1
11
20
1
DW SUFFIX
SOIC
CASE 751D-03
ORDERING INFORMATION
SN54LSXXXJ
Ceramic
SN74LSXXXN Plastic
SN74LSXXXDW SOIC
1
1G
2
1A1
3
4
5
6
1A3
7
8
9
10
GND
2Y4 1A2 2Y3
2Y2 1A4 2Y1
SN54 / 74LS244
VCC 2G
20
19
1Y1
18
2A4 1Y2
17
16
2A3
15
1Y3 2A2 1Y4
14
13
12
2A1
11
1
1G
2
1A1
3
4
5
6
1A3
7
8
9
10
GND
2Y4 1A2 2Y3
2Y2 1A4 2Y1
FAST AND LS TTL DATA
5-387
SN54/74LS240
•
SN54/74LS241
•
SN54/74LS244
TRUTH TABLES
SN54 / 74LS240
INPUTS
OUTPUT
1G, 2G
L
L
H
D
L
H
X
H
L
(Z)
1G, 2G
L
L
H
D
L
H
X
L
H
(Z)
SN54 / 74LS244
INPUTS
OUTPUT
SN54 / 74LS241
INPUTS
1G
L
L
H
D
L
H
X
OUTPUT
2G
L
H
(Z)
H
H
L
D
L
H
X
L
H
(Z)
INPUTS
OUTPUT
H = HIGH Voltage Level
L = LOW Voltage Level
X = Immaterial
Z = HIGH Impedance
GUARANTEED OPERATING RANGES
Symbol
VCC
TA
IOH
Supply Voltage
Operating Ambient Temperature Range
Output Current — High
Parameter
54
74
54
74
54, 74
54
74
IOL
Output Current — Low
54
74
Min
4.5
4.75
– 55
0
Typ
5.0
5.0
25
25
Max
5.5
5.25
125
70
– 3.0
– 12
– 15
12
24
Unit
V
°C
mA
mA
mA
FAST AND LS TTL DATA
5-388
SN54/74LS240
•
SN54/74LS241
•
SN54/74LS244
DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE
(unless otherwise specified)
Limits
Symbol
VIH
VIL
VT+–VT–
VIK
VOH
Parameter
Input HIGH Voltage
54
Input LOW Voltage
74
Hysteresis
Input Clamp Diode Voltage
54, 74
Output HIGH Voltage
54, 74
54, 74
VOL
IOZH
IOZL
IIH
IIL
IOS
Output LOW Voltage
74
Output Off Current HIGH
Output Off Current LOW
Input HIGH Current
0.1
Input LOW Current
Output Short Circuit Current (Note 1)
Power Supply Current
Total, Output HIGH
Total, Output LOW
ICC
Total at HIGH Z
LS240
LS241/244
LS240
LS241/244
– 40
– 0.2
– 225
27
44
46
50
54
mA
VCC = MAX
0.35
0.5
20
– 20
20
V
µA
µA
µA
mA
mA
mA
2.0
0.25
0.4
V
V
2.4
0.2
0.4
– 0.65
3.4
– 1.5
0.8
V
V
V
Min
2.0
0.7
V
Typ
Max
Unit
V
Test Conditions
Guaranteed Input HIGH Voltage for
All Inputs
Guaranteed Input LOW Voltage for
All Inputs
VCC = MIN
VCC = MIN, IIN = – 18 mA
VCC = MIN, IOH = – 3.0 mA
VCC = MIN, IOH = MAX
IOL = 12 mA
IOL = 24 mA
VCC = VCC MIN,
VIN = VIL or VIH
per Truth Table
VCC = MAX, VOUT = 2.7 V
VCC = MAX, VOUT = 0.4 V
VCC = MAX, VIN = 2.7 V
VCC = MAX, VIN = 7.0 V
VCC = MAX, VIN = 0.4 V
VCC = MAX
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)
Limits
Symbol
tPLH
tPHL
tPLH
tPHL
tPZH
tPZL
tPLZ
tPHZ
Parameter
Propagation Delay, Data to Output
LS240
Propagation Delay, Data to Output
LS241 / 244
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
CL = 5.0 pF,
RL = 667
Ω
CL = 45 pF,
RL = 667
Ω
Test Conditions
FAST AND LS TTL DATA
5-389
SN54/74LS240
•
SN54/74LS241
•
SN54/74LS244
AC WAVEFORMS
VIN
1.3 V
tPLH
1.3 V
tPHL
1.3 V
VCC
VOUT
1.3 V
RL
Figure 1
SW1
TO OUTPUT
UNDER TEST
VIN
1.3 V
tPHL
1.3 V
tPLH
1.3 V
CL*
5 k
Ω
VOUT
1.3 V
SW2
Figure 2
VE
VE
1.3 V
tPZL
1.3 V
1.3 V
tPLZ
SWITCH POSITIONS
≈
1.3 V
VOL
VOUT
0.5 V
Figure 3
Figure 5
VE
1.3 V
VE
tPZH
VOUT
1.3 V
1.3 V
tPHZ
≥
VOH
0.5 V
≈
1.3 V
Figure 4
FAST AND LS TTL DATA
5-390
Case 751D-03 DW Suffix
20-Pin Plastic
SO-20 (WIDE)
-A-
20
11
NOTES:
1.
DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
2.
3.
CONTROLLING DIMENSION: MILLIMETER.
DIMENSION A AND B DO NOT INCLUDE MOLD
PROTRUSION.
4.
MAXIMUM MOLD PROTRUSION 0.15 (0.006) PER
SIDE.
-B-
1
10
P
0.25 (0.010)
M
B
M
5.
751D 01, AND 02 OBSOLETE, NEW STANDARD
751D 03.
10 PL
G
R X 45°
-T-
C
K
M
SEATING
PLANE
M
D
20 PL
0.25 (0.010)
T
B
S
F
J
DIM
A
B
C
D
F
G
J
K
M
P
R
MILLIMETERS
MIN
MAX
12.65
7.40
2.35
0.35
0.50
12.95
7.60
2.65
0.49
0.90
INCHES
MIN
MAX
0.499
0.292
0.093
0.014
0.020
0.510
0.299
0.104
0.019
0.035
1.27 BSC
0.25
0.10
0
0.32
0.25
7
0.050 BSC
0.010
0.004
0
0.012
0.009
7
°
°
°
°
10.05
0.25
10.55
0.75
0.395
0.010
0.415
0.029
A
S
Case 732-03 J Suffix
20-Pin Ceramic Dual In-Line
NOTES:
1.
LEADS WITHIN 0.25 mm (0.010) DIA., TRUE
POSITION AT SEATING PLANE, AT MAXIMUM
20
1
11
2.
MATERIAL CONDITION.
DIM L TO CENTER OF LEADS WHEN FORMED
PARALLEL.
10
3.
DIM A AND B INCLUDES MENISCUS.
B
A
F
C
L
N
H
D
SEATING
PLANE
J
M
G
K
DIM
A
B
C
D
F
G
H
J
K
L
M
N
MILLIMETERS
MIN
MAX
23.88
6.60
3.81
0.38
1.40
25.15
7.49
5.08
0.56
1.65
INCHES
MIN
MAX
0.940
0.260
0.150
0.015
0.055
0.990
0.295
0.200
0.022
0.065
2.54 BSC
0.51
0.20
3.18
1.27
0.30
4.06
0.100 BSC
0.020
0.008
0.125
0.050
0.012
0.160
7.62 BSC
0
°
15
°
0.300 BSC
0
°
15
°
0.25
1.02
0.010
0.040
Case 738-03 N Suffix
20-Pin Plastic
-A-
20
1
11
10
NOTES:
1.
DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
2.
3.
CONTROLLING DIMENSION: INCH.
DIMENSION L" TO CENTER OF LEAD WHEN
FORMED PARALLEL.
B
C
L
4.
DIMENSION B" DOES NOT INCLUDE MOLD
FLASH.
5.
738 02 OBSOLETE, NEW STANDARD 738 03.
-T-
SEATING
PLANE
K
E
G
F
D
20 PL
0.25 (0.010)
M
N
M
J
20 PL
0.25 (0.010)
T
A
M
M
T
B
M
DIM
A
B
C
D
E
F
G
J
K
L
M
N
MILLIMETERS
MIN
MAX
25.66
6.10
3.81
0.39
27.17
6.60
4.57
0.55
INCHES
MIN
MAX
1.010
0.240
0.150
0.015
1.070
0.260
0.180
0.022
1.27 BSC
1.27
1.77
0.050 BSC
0.050
0.070
2.54 BSC
0.21
2.80
0.38
3.55
0.100 BSC
0.008
0.110
0.015
0.140
7.62 BSC
0
°
15
°
0.300 BSC
0
°
15
°
0.51
1.01
0.020
0.040
FAST AND LS TTL DATA
5-391
嵌入式系统
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