SN74LS640, SN74LS641, SN74LS642, SN74LS645
Octal Bus Transceivers
These octal bus transceivers are designed for asynchr...
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...