Page 1
OUTPUT
OUTPUT
OUTPUT
OUTPUT
SN54/74LS242
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
LOGIC AND CONNECTION DIAGRAMS DIP (TOP VIEW)
SN54/74LS242
VCCGBA NC 1B 2B 3B 4B
14 13 12 11 10 9
123456
G
BA NC 1A 2A 3A 4A GND
SN54/74LS243
VCCGBA NC 1B 2B 3B 4B
14 13 12 11 10 9
8
7
NOTE:
The Flatpak version
has the same pinouts
(Connection Diagram) as
the Dual In-Line Package.
8
SN54/74LS243
QUAD BUS TRANSCEIVER
LOW POWER SCHOTTKY
J SUFFIX
CERAMIC
14
1
14
1
14
1
CASE 632-08
N SUFFIX
PLASTIC
CASE 646-06
D SUFFIX
SOIC
CASE 751A-02
123456
G
BA NC 1A 2A 3A 4A GND
7
SN54/74LS242
INPUTS
GAB D
L L H L X (Z)
L H L H L H
H X (Z) H H L
INPUTS
GAB D
TRUTH TABLES
INPUTS
GAB D
L L L L X (Z)
L H H H L H
H X (Z) H H L
H = HIGH Voltage Level
L = LOW Voltage Level
X = Immaterial
Z = HIGH Impedance
FAST AND LS TTL DAT A
5-1
ORDERING INFORMATION
SN54LSXXXJ Ceramic
SN74LSXXXN Plastic
SN74LSXXXDW SOIC
SN54/74LS243
INPUTS
GAB D
Page 2
SN54/74LS242 • SN54/74LS243
VILI
LOW Volt
V
pg
VOHOutput HIGH Volt
VOLOutput LOW Volt
V
V
V
CC
CC
Total at HIGH Z
GUARANTEED OPERATING RANGES
Symbol Parameter Min Typ Max Unit
V
CC
T
A
I
OH
I
OL
DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE (unless otherwise specified)
Symbol Parameter
V
IH
VT+–V
V
IK
I
OZH
I
OZL
I
IH
I
IL
I
OS
I
CC
Note 1: Not more than one output should be shorted at a time, nor for more than 1 second.
Supply Voltage 54
Operating Ambient Temperature Range 54
Output Current — High
Output Current — Low 54
Limits
Min Typ Max
Input HIGH Voltage 2.0 V
54 0.7
74 0.8
54, 74 2.4 3.4 V VCC = MIN, IOH = –3.0 mA
54, 74 2.0 V VCC = MIN, IOH = MAX
54, 74 0.25 0.4 V IOL = 12 mA
74 0.35 0.5 V IOL = 24 mA
D, E1, E
2
E1, E
2
D Input 0.1 mA VCC = MAX, VIN = 5.5 V
LS242 50
LS243 54
T–
nput
Hysteresis 0.2 0.4 V VCC = MIN
Input Clamp Diode Voltage –0.65 –1.5 V VCC = MIN, IIN = –18 mA
Output Off Current HIGH 40 µA VCC = MAX, V
Output Off Current LOW –200 µA VCC = MAX, V
Input HIGH Current
Input LOW Current –0.2 mA VCC = MAX, VIN = 0.4 V
Output Short Circuit Current (Note 1) –40 –225 mA VCC = MAX
Power Supply Current
Total, Output HIGH
Total, Output LOW 50
age
age
age
74
74
54, 74 –3.0 mA
54
74
74
20 µA VCC = MAX, VIN = 2.7 V
0.1 mA VCC = MAX, VIN = 7.0 V
38
4.5
4.75
–55
0
Unit Test Conditions
Guaranteed Input HIGH Voltage for
All Inputs
Guaranteed Input LOW Voltage for
All Inputs
mA VCC = MAX
5.0
5.0
25
25
OUT
OUT
5.5
5.25
125
70
–12
–15
12
24
VCC = VCC MIN,
=
or
IN
IL
per Truth Table
= 2.7 V
= 0.4 V
IH
V
°C
mA
mA
FAST AND LS TTL DATA
5-2
Page 3
SN54/74LS242 • SN54/74LS243
C
L
L
p,
AC CHARACTERISTICS (T
Symbol Parameter
t
PLH
t
PHL
t
PZH
t
PZL
t
PLZ
t
PHZ
Propagation Delay, Data to Output
Output Enable Time to HIGH Level 15 23 15 23 ns
Output Enable Time to LOW Level 20 30 20 30 ns
Output Disable Time from LOW Level 15 25 15 25 ns
Output Disable Time from HIGH Level 10 18 10 18 ns
V
IN
V
OUT
A
1.3 V 1.3 V
1.3 V
= 25°C, VCC = 5.0 V)
t
PLH
Figure 1
Limits
LS242 LS243
Min Typ Max Min Typ Max
9.01214
18
121218
AC WAVEFORMS
t
PHL
1.3 V
Unit Test Conditions
18
ns
SW1
V
CC
R
C
= 45
= 45 pF,
RL = 667 Ω
CL = 5.0 pF,
RL = 667 Ω
L
F
V
V
V
V
E
E
V
E
E
OUT
V
OUT
IN
OUT
1.3 V
t
PHL
1.3 V
V
V
Figure 2
1.3 V 1.3 V
t
PZL
1.3 V
Figure 3
1.3 V 1.3 V
t
PZH
1.3 V
1.3 V
0.5 V
t
PLH
1.3 V
t
PLZ
t
PHZ
0.5 V
V
≥
≈
≈
OL
V
1.3 V
OH
1.3 V
TO OUTPUT
UNDER TEST
SYMBOL SW1 SW2
t
PZH
t
PZL
t
PLZ
t
PHZ
Ω
5 k
SW2CL*
SWITCH POSITIONS
Open Closed
Closed Open
Closed Closed
Closed Closed
Figure 5
Figure 4
FAST AND LS TTL DATA
5-3
Loading...