Document
SN74LS640, SN74LS641, SN74LS642, SN74LS645
Octal Bus Transceivers
These octal bus transceivers are designed for asynchronous two-way communication between data buses. Control function implementation minimizes external timing requirements. These circuits allow data transmission from the A bus to B or from the B bus to A bus depending upon the logic level of the direction control (DIR) input. Enable input (G) can disable the device so that the buses are effectively isolated.
DEVICE LS640 LS641 LS642 LS645
OUTPUT 3-State Open-Collector Open-Collector 3-State
LOGIC Inverting
True Inverting
True
CONTROL INPUTS
G
DIR
FUNCTION TABLE OPERATION
LS640 LS642
LS641 LS645
L
L
B data to A bus
B data to A bus
L
H
A data to B bus
A data to B bus
H
X
Isolation
Isolation
H = HIGH Level, L = LOW Level, X = Irrelevant
GUARANTEED OPERATING RANGES (SN74LS640, SN74LS645)
Symbol
Parameter
Min Typ Max Unit
VCC
Supply Voltage
TA
Operating Ambient
Temperature Range
4.75 5.0 5.25
V
0
25
70
°C
IOH
Output Current − High
−3.0 mA −15 mA
IOL
Output Current − Low
24
mA
GUARANTEED OPERATING RANGES (SN74LS641, SN74LS642)
Symbol
Parameter
Min Typ Max Unit
VCC
Supply Voltage
TA
Operating Ambient
Temperature Range
4.75 5.0 5.25
V
0
25
70
°C
VOH
Output Voltage − High
IOL
Output Current − Low
5.5
V
24
mA
20 1
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LOW POWER SCHOTTKY
MARKING DIAGRAMS
SN74LS64xN AWLYYWW
1 PDIP−20 N SUFFIX CASE 738
20 1
LS64y AWLYYWW
1 SOIC−20 DW SUFFIX CASE 751D
20 1
1 1
SOEIAJ−20 M SUFFIX CASE 967
74LS64y AWLYWW
x = 0, 1, 2, or 5 y = 0, 1, or 2 A = Assembly Location WL = Wafer Lot Y, YY= Year WW = 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
1
July, 2006 − Rev. 11
Publication Order Number: SN74LS640/D
SN74LS640, SN74LS641, SN74LS642, SN74LS645
CONNECTION DIAGRAMS DIP (TOP VIEW)
ENABLE VCC G B1 B2 B3 B4 B5 B6 B7 B8
20 19 18 17 16 15 14 13 12 11
ENABLE VCC G B1 B2 B3 B4 B5 B6 B7 B8
20 19 18 17 16 15 14 13 12 11
1 2 3 4 5 6 7 8 9 10 DIR A1 A2 A3 A4 A5 A6 A7 A8 GND
Figure 1. SN74LS640 SN74LS642
1 2 3 4 5 6 7 8 9 10 DIR A1 A2 A3 A4 A5 A6 A7 A8 GND
Figure 2. SN74LS641 SN74LS645
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SN74LS640, SN74LS641, SN74LS642, SN74LS645
SN74LS640 • SN74LS645
DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE (unless otherwise specified)
Limits
Symbol VIH
Parameter Input HIGH Voltage
Min Typ Max Unit
Test Conditions
2.0
V
Guaranteed Input HIGH Voltage for All Inputs
VIL
Input LOW Voltage
0.6
V
Guaranteed Input LOW Voltage for All Inputs
VIK VOH
VOL IOZH IOZL
IIH IIL IOS
ICC
Input Clamp Diode Voltage
−0.65 −1.5
V
VCC = MIN, IIN = − 18 mA
Output HIGH Voltage
2.4
3.4
2.0
V
VCC = MIN, IOH = 3.0 mA
V
VCC = MIN, IOH = MAX
Output LOW Voltage
0.25 0.4 0.35 0.5
V
IOL = 12 mA
V
IOL = 24 mA
VCC = VCC MIN, VIN = VIL or VIH per Truth Table
Output Off Current HIGH
20
μA VCC = MAX, VOUT = 2.7 V
Output Off Current LOW
− 400 μA VCC = MAX, VOUT = 0.4 V
A or B, DIR or G
20
μA VCC = MAX, VIN = 2.7 V
Input HIGH Current DIR or G
0.1
mA VCC = MAX, VIN = 7.0 V
A or B
0.1
mA VCC = MAX, VIN = 5.5 V
Input LOW Current
− 0.4 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
70
90
mA VCC = MAX
Total at HIGH Z
95
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
LS640
LS645
Symbol
Parameter
Min Typ Max Min Typ Max Unit
tPLH
Propagation Delay
tPHL
A to B
6.0 10 8.0 15
8.0 15 11 15
ns
tPLH
Propagation Delay
tPHL
B to A
6.0 10 8.0 15
8.0 15 11 15
ns
tPZL
Output Enable Time
tPZH
G, DIR to A
31 40 23 40
31 26
40 40
ns
tPZL
Output Enable Time
tPZH
G, DIR to B
31 40 23 40
31 26
40 40
ns
tPLZ
Output Disable Time
tPHZ
G, DIR to A
15 25 15 25
15 15
25 25
ns
tPLZ
Output Disable Time
tPHZ
G, DIR to B
15 25 15 25
15 15
25 25
ns
Test Conditions CL = 45 pF, RL = 667 Ω CL = 5.0 pF
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SN74LS640, SN74LS641, SN74LS642, SN74LS645
SN74LS641 • SN74LS642
DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE (unless otherwise specified)
Limits
Symbol VIH
Parameter Input HIGH Voltage
Min Typ Max Unit
Test Conditions
2.0
V
Guaranteed Input HIGH Voltage for All Inputs
VIL
Input LOW Voltage
0.6
V
Guaranteed Input LOW Voltage for All Inputs
VIK
Input Clamp Diode Voltage
IOH
Output HIGH Current
VOL
Output LOW Voltage
IIH
Input HIGH Current
IIL
Input LOW Current
Power Supply Current Total, Output HIGH
ICC
Total, Output LOW
−0.65 −1.5
V
VCC = MIN, IIN = − 18 mA
100
μA
VCC = MIN, VOH = MAX
0.25 0.4 0.35 0.5
V
IOL = 12 mA
V
IOL = 24 mA
VCC = VCC MIN, VIN = VIL or VIH per Truth Table
20
μA.