Texas Instruments SN54ALS645AJ, SN54AS645J, SN74ALS645A-1DW, SN74ALS645A-1DWR, SN74ALS645A-1N Datasheet
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SN54ALS645A, SN54AS645, SN74ALS645A, SN74AS645
OPERATION
OCTAL BUS TRANSCEIVERS
WITH 3-STATE OUTPUTS
SDAS278 – JANUARY 1995
• Bidirectional Bus Transceivers in
High-Density 20-Pin Packages
• True Logic
• 3-State Outputs
• Package Options Include Plastic
Small-Outline (DW) Packages, Ceramic
Chip Carriers (FK), and Standard Plastic (N)
and Ceramic (J) 300-mil DIPs
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 on the level at the direction-control
(DIR) input. The output-enable (OE
used to disable the device so that the buses are
effectively isolated.
The -1 version of the SN74ALS645A is identical
to the standard version, except that the
recommended maximum IOL is increased to
48 mA. There is no -1 version of the
SN54ALS645A.
The SN54ALS645A and SN54AS645 are
characterized for operation over the full military
temperature range of –55°C to 125°C. The
SN74ALS645A and SN74AS645 are
characterized for operation from 0°C to 70°C.
) input can be
SN54ALS645A, SN54AS645 ...J PACKAGE
SN74ALS645A, SN74AS645 . . . DW OR N PACKAGE
SN54ALS645A, SN54AS645 . . . FK PACKAGE
A3
A4
A5
A6
A7
(TOP VIEW)
DIR
1
A1
2
A2
3
A3
4
A4
5
A5
6
A6
7
A7
8
9
A8
10
GND
(TOP VIEW)
A2A1DIR
3212019
4
5
6
7
8
9
10 11 12 13
A8
B8
20
19
18
17
16
15
14
13
12
11
V
CC
B7
OE
18
17
16
15
14
B6
V
OE
B1
B2
B3
B4
B5
B6
B7
B8
CC
B1
B2
B3
B4
B5
GND
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.
FUNCTION TABLE
INPUTS
OE DIR
L L B data to A bus
L H A data to B bus
H X Isolation
Copyright 1995, Texas Instruments Incorporated
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
1
SN54ALS645A, SN54AS645, SN74ALS645A, SN74AS645
UNIT
IOLLow-level output current
mA
OCTAL BUS TRANSCEIVERS
WITH 3-STATE OUTPUTS
SDAS278 – JANUARY 1995
19
1
2
3
4
5
6
7
8
9
†
G3
3 EN1 [BA]
3 EN2 [AB]
1
logic diagram (positive logic)
19
OE
1
18
B1
2
17
16
15
14
13
12
11
B2
B3
B4
B5
B6
B7
B8
DIR
A1
182
To Seven Other Transceivers
logic symbol
OE
DIR
A1
A2
A3
A4
A5
A6
A7
A8
†
This symbol is in accordance with ANSI/IEEE Std 91-1984 and
IEC Publication 617-12.
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
Supply voltage, V
Input voltage, V
Operating free-air temperature range, T
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.
7 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CC
: All inputs 7 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
I
I/O ports 5.5 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
: SN54ALS645A –55°C to 125°C. . . . . . . . . . . . . . . . . . . . . . . . . . .
A
SN74ALS645A 0°C to 70°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B1
‡
recommended operating conditions
V
CC
V
IH
V
IL
I
OH
T
A
§
Applies only to the -1 version and only if VCC is between 4.75 V and 5.25 V
2
SN54ALS645A SN74ALS645A
MIN NOM MAX MIN NOM MAX
Supply voltage 4.5 5 5.5 4.5 5 5.5 V
High-level input voltage 2 2 V
Low-level input voltage 0.7 0.8 V
High-level output current –12 –15 mA
p
Operating free-air temperature –55 125 0 70 °C
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
12 24
48
§
SN54ALS645A, SN54AS645, SN74ALS645A, SN74AS645
PARAMETER
TEST CONDITIONS
UNIT
V
V
I
V
V
mA
I
V
V
V
A
I
V
V
V
mA
A or B
B
A
ns
OE
A
B
ns
OE
A
B
ns
OCTAL BUS TRANSCEIVERS
WITH 3-STATE OUTPUTS
SDAS278 – JANUARY 1995
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
SN54ALS645A SN74ALS645A
MIN TYP†MAX MIN TYP†MAX
V
IK
OH
V
OL
I
IH
IL
I
O
I
CC
†
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.
¶
The output conditions have been chosen to produce a current that closely approximates one half of the true short-circuit output current, IOS.
Control inputs
A or B ports
Control inputs
A or B ports
Control inputs
A or B ports
¶
VCC = 4.5 V, II = –18 mA –1.5 –1.5 V
VCC = 4.5 V to 5.5 V, IOH = –0.4 mA VCC –2 VCC –2
IOH = –3 mA 2.4 3.2 2.4 3.2
VCC = 4.5 V
VCC = 4.5 V
= 5.5
CC
= 5.5 V,
§
§
CC
= 5.5 V,
CC
VCC = 5.5 V, VO = 2.25 V –20 –112 –30 –112 mA
VCC = 5.5 V
IOH = –12 mA 2
IOH = –15 mA 2
IOL = 12 mA 0.25 0.4 0.25 0.4
IOL = 24 mA 0.35 0.5
IOL = 48 mA
VI = 7 V 0.1 0.1
VI = 5.5 V 0.1 0.1
= 2.7
I
= 0.4
I
Outputs high 30 48 30 45
Outputs low 36 60 36 55
Outputs disabled 38 63 38 58
‡
20 20
20 20
–0.1 –0.1
–0.1 –0.1
0.35 0.5
V
µ
mA
switching characteristics (see Figure 1)
VCC = 4.5 V to 5.5 V,
CL = 50 pF,
PARAMETER
t
PLH
t
PHL
t
PZH
t
PZL
t
PHZ
t
#
For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.
PLZ
FROM
(INPUT)
TO
(OUTPUT)
or
or
or
R1 = 500 Ω
R2 = 500 Ω,
TA = MIN to MAX
SN54ALS645A SN74ALS645A
MIN MAX MIN MAX
1 19 3 10
1 14 3 10
2 30 5 20
2 29 5 20
2 14 2 10
2 30 4 15
,
#
UNIT
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
3
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