SN54/74LS242
SN54/74LS243
QUAD BUS TRANSCEIVER
The SN54/ 74LS242 and SN54 / 74LS243 are Quad Bus Transmitters / Receivers designed for 4-line asynchronous 2-way data communications
between data buses.
• Hysteresis at Inputs to Improve Noise Immunity
• 2-Way Asynchronous Data Bus Communication
• Input Clamp Diodes Limit High-Speed Termination Effects
QUAD BUS TRANSCEIVER
LOW POWER SCHOTTKY
LOGIC AND CONNECTION DIAGRAMS DIP (TOP VIEW)
SN54 / 74LS242
VCC
GBA
NC
1B
2B
3B
4B
14
13
12
11
10
9
8
J SUFFIX
CERAMIC
CASE 632-08
14
1
1
2
3
4
5
6
7
GBA
NC
1A
2A
3A
4A
GND
SN54 / 74LS243
VCC
GBA
NC
1B
2B
3B
4B
14
13
12
11
10
9
8
N SUFFIX
PLASTIC
CASE 646-06
14
NOTE:
The Flatpak version
has the same pinouts
(Connection Diagram) as
the Dual In-Line Package.
1
D SUFFIX
SOIC
CASE 751A-02
14
1
ORDERING INFORMATION
1
2
3
4
5
6
7
GBA
NC
1A
2A
3A
4A
GND
SN54LSXXXJ
Ceramic
SN74LSXXXN Plastic
SN74LSXXXDW SOIC
TRUTH TABLES
SN54/74LS243
SN54 / 74LS242
INPUTS
INPUTS
OUTPUT
GAB
D
L
L
H
L
H
X
H
L
(Z)
INPUTS
OUTPUT
GAB
D
L
H
H
X
L
H
INPUTS
OUTPUT
(Z)
H
L
GAB
D
L
L
H
L
H
X
H = HIGH Voltage Level
L = LOW Voltage Level
X = Immaterial
Z = HIGH Impedance
FAST AND LS TTL DATA
5-393
L
H
(Z)
OUTPUT
GAB
D
L
H
H
X
L
H
(Z)
H
L
SN54/74LS242 • SN54/74LS243
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
TA
Operating Ambient Temperature Range
54
74
– 55
0
25
25
125
70
°C
IOH
Output Current — High
54, 74
– 3.0
mA
54
74
– 12
– 15
mA
54
74
12
24
mA
IOL
Output Current — Low
DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE (unless otherwise specified)
Limits
Symbol
Min
Parameter
VIH
Input HIGH Voltage
VIL
Input LOW Voltage
VT+–VT–
Hysteresis
VIK
Input Clamp Diode Voltage
VOH
Output HIGH Voltage
VOL
Output LOW Voltage
IOZH
Output Off Current HIGH
IOZL
Output Off Current LOW
IIH
Input HIGH Current
Max
Unit
2.0
54
0.7
74
0.8
0.2
0.4
– 0.65
54, 74
2.4
54, 74
2.0
– 1.5
3.4
Test Conditions
V
Guaranteed Input HIGH Voltage for
All Inputs
V
Guaranteed Input LOW Voltage for
All Inputs
V
VCC = MIN
V
VCC = MIN, IIN = – 18 mA
V
VCC = MIN, IOH = – 3.0 mA
V
VCC = MIN, IOH = MAX
VCC = VCC MIN,
VIN = VIL or VIH
per Truth Table
54, 74
0.25
0.4
V
IOL = 12 mA
74
0.35
0.5
V
IOL = 24 mA
40
µA
VCC = MAX, VOUT = 2.7 V
– 200
µA
VCC = MAX, VOUT = 0.4 V
D, E1, E2
20
µA
VCC = MAX, VIN = 2.7 V
E1, E2
0.1
mA
VCC = MAX, VIN = 7.0 V
D Input
0.1
mA
VCC = MAX, VIN = 5.5 V
– 0.2
mA
VCC = MAX, VIN = 0.4 V
– 225
mA
VCC = MAX
mA
VCC = MAX
IIL
Input LOW Current
IOS
Output Short Circuit Current (Note 1)
ICC
Typ
– 40
Power Supply Current
Total, Output HIGH
38
Total, Output LOW
50
LS242
50
LS243
54
Total at HIGH Z
Note 1: Not more than one output should be shorted at a time, nor for more than 1 second.
FAST AND LS TTL DATA
5-394
SN54/74LS242 • SN54/74LS243
AC CHARACTERISTICS (TA = 25°C, VCC = 5.0 V)
Limits
LS242
Symbol
Parameter
Min
LS243
Typ
Max
Min
Typ
Max
Unit
tPLH
tPHL
Propagation Delay, Data to Output
9.0
12
14
18
12
12
18
18
ns
tPZH
Output Enable Time to HIGH Level
15
23
15
23
ns
tPZL
Output Enable Time to LOW Level
20
30
20
30
ns
tPLZ
Output Disable Time from LOW Level
15
25
15
25
ns
tPHZ
Output Disable Time from HIGH Level
10
18
10
18
ns
Test Conditions
CL = 45 pF,
RL = 667 Ω
CL = 5.0 pF,
RL = 667 Ω
AC WAVEFORMS
Figure 1
Ω
Figure 2
SWITCH POSITIONS
≈ Figure 3
SYMBOL
SW1
SW2
tPZH
Open
Closed
tPZL
Closed
Open
tPLZ
Closed
Closed
tPHZ
Closed
Closed
Figure 5
≥
≈ Figure 4
FAST AND LS TTL DATA
5-395
Case 751A-02 D Suffix
14-Pin Plastic
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FAST AND LS TTL DATA
5-396
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◊
FAST AND LS TTL DATA
5-397