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
http://onsemi.com
LOW
POWER
SCHOTTKY
LOGIC
Inverting
True
Inverting
True
MARKING
DIAGRAMS
SN74LS64xN
AWLYYWW
FUNCTION TABLE
CONTROL
INPUTS
1
20
1
OPERATION
G
DIR
LS640
LS642
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
PDIP−20
N SUFFIX
CASE 738
LS641
LS645
Isolation
LS64y
AWLYYWW
20
H = HIGH Level, L = LOW Level, X = Irrelevant
1
1
GUARANTEED OPERATING RANGES (SN74LS640, SN74LS645)
VCC
Parameter
Supply Voltage
TA
Operating Ambient
Temperature Range
IOH
Min
Typ
Max
Unit
4.75
5.0
5.25
V
0
25
70
°C
−3.0
mA
−15
Symbol
mA
24
mA
Output Current − High
IOL
Output Current − Low
GUARANTEED OPERATING RANGES (SN74LS641, SN74LS642)
Symbol
VCC
Parameter
Supply Voltage
SOIC−20
DW SUFFIX
CASE 751D
Min
Typ
Max
5.0
5.25
V
0
25
70
°C
20
1
1
1
SOEIAJ−20
M SUFFIX
CASE 967
Unit
4.75
74LS64y
AWLYWW
TA
Operating Ambient
Temperature Range
VOH
Output Voltage − High
5.5
V
IOL
Output Current − Low
24
x
= 0, 1, 2, or 5
y
= 0, 1, or 2
A
= Assembly Location
WL = Wafer Lot
Y, YY= Year
WW = Work Week
mA
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
July, 2006 − Rev. 11
1
Publication Order Number:
SN74LS640/D
