Texas Instruments SN74ALS641A-1DW, SN74ALS641A-1DWR, SN74ALS641A-1N, SN74ALS641ADW, SN74ALS641ADWR Datasheet
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SN74ALS641A, SN74ALS642A, SN74AS641
OCTAL BUS TRANSCEIVERS
WITH OPEN-COLLECTOR OUTPUTS
SDAS300 – MARCH 1995
Copyright 1995, Texas Instruments Incorporated
1
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
• Bidirectional Bus Transceivers in
High-Density 20-Pin Packages
• Choice of True or Inverting Logic
• Package Options Include Plastic
Small-Outline (DW) Packages and
Standard Plastic (N) 300-mil DIPs
DEVICE
LOGIC
SN74ALS641A, SN74AS641 True
SN74ALS642A Inverting
description
These octal bus transceivers are designed for
asynchronous two-way communication between
data buses. These devices transmit data from the A bus to the B bus or from the B bus to the A bus, depending
upon the level at the direction-control (DIR) input. The output-enable (OE
) input disables the device so that the
buses are effectively isolated.
The -1 versions of the SN74ALS641A and SN74ALS642A are identical to the standard versions, except that
the recommended maximum I
OL
is increased to 48 mA in the -1 versions.
The SN74ALS641A, SN74ALS642A, and SN74AS641 are characterized for operation from 0°C to 70°C.
FUNCTION TABLE
INPUTS
OPERATION
OE DIR
SN74ALS641A
SN74AS641
SN74ALS642A
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
logic symbols
†
B2
17
B3
16
B4
15
A5
6
A6
7
A7
8
A8
9
A2
3
A3
4
A4
5
OE
A1
2
G3
19
3 EN2 [AB]
B5
14
B6
13
B7
12
B8
11
B1
18
3 EN1 [BA]
1
DIR
1
2
SN74ALS641A, SN74AS641
B2
17
B3
16
B4
15
A5
6
A6
7
A7
8
A8
9
A2
3
A3
4
A4
5
OE
A1
2
G3
19
3 EN2 [AB]
B5
14
B6
13
B7
12
B8
11
B1
18
3 EN1 [BA]
1
DIR
1
2
SN74ALS642A
†
These symbols are in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
DIR
A1
A2
A3
A4
A5
A6
A7
A8
GND
V
CC
OE
B1
B2
B3
B4
B5
B6
B7
B8
DW OR N PACKAGE
(TOP VIEW)
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
SN74ALS641A, SN74ALS642A, SN74AS641
OCTAL BUS TRANSCEIVERS
WITH OPEN-COLLECTOR OUTPUTS
SDAS300 – MARCH 1995
2
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
logic diagrams (positive logic)
SN74ALS641A, SN74AS641
A1
B1
19
1
18
2
OE
DIR
To Seven Other Transceivers
SN74ALS642A
A1
B1
19
1
18
2
OE
DIR
To Seven Other Transceivers
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
†
Supply voltage, V
CC
7 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input voltage, V
I
: All inputs and I/O ports 7 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating free-air temperature range, T
A
: SN74ALS641A, SN74ALS642A 0°C to 70°C. . . . . . . . . . . . . . . . .
Storage temperature range –65°C to 150°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
†
Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and
functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
recommended operating conditions
SN74ALS641A
SN74ALS642A
UNIT
MIN NOM MAX
V
CC
Supply voltage 4.5 5 5.5 V
V
IH
High-level input voltage 2 V
V
IL
Low-level input voltage 0.8 V
V
OH
High-level output voltage 5.5 V
p
24
IOLLow-level output current
48
‡
mA
T
A
Operating free-air temperature 0 70 °C
‡
Applies only to the -1 version and only if VCC is between 4.75 V and 5.25 V
SN74ALS641A, SN74ALS642A, SN74AS641
OCTAL BUS TRANSCEIVERS
WITH OPEN-COLLECTOR OUTPUTS
SDAS300 – MARCH 1995
3
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
PARAMETER TEST CONDITIONS
SN74ALS641A
SN74ALS642A
UNIT
MIN TYP†MAX
V
IK
VCC = 4.5 V, II = –18 mA –1.5 V
I
OH
VCC = 4.5 V, VOH = 5.5 V 0.1 mA
IOL = 12 mA 0.25 0.4
V
OL
VCC = 4.5 V
IOL = 24 mA 0.35 0.5
V
IOL = 48 mA
‡
0.35 0.5
I
I
Control inputs VCC = 5.5 V, VI = 7 V 0.1 mA
Control inputs
20
I
IH
A or B ports
§
V
CC
=
5.5 V
,
V
I
=
2.7 V
20
µ
A
Control inputs
–0.1
I
IL
A or B ports
§
V
CC
= 5.5 V,
V
I
= 0.4
V
–0.1
mA
Outputs high 25 37
SN74ALS641A
V
CC
= 5.5
V
Outputs low 33 47
I
CC
Outputs high 8 15
mA
SN74ALS642A
V
CC
=
5.5 V
Outputs low 18 28
†
All typical values are at VCC = 5 V, TA = 25°C.
‡
Applies only to the -1 version and only if VCC is between 4.75 V and 5.25 V
§
For I/O ports, the parameters IIH and IIL include the off-state output current.
switching characteristics (see Figure 1)
PARAMETER
FROM
(
INPUT
)
TO
(
OUTPUT
)
VCC = 4.5 V to 5.5 V,
CL = 50 pF,
RL = 680 Ω
,
TA = MIN to MAX
¶
UNIT
(INPUT)
(OUTPUT)
SN74ALS641A SN74ALS642A
MIN MAX MIN MAX
t
PLH
5 25 10 30
t
PHL
A or B
B
or
A
3 18 5 22
ns
t
PLH
8 30 10 30
t
PHL
OE
A
or
B
8 30 15 38
ns
t
PLH
8 32 10 30
t
PHL
DIR
A
or
B
8 32 15 38
ns
¶
For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.
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