SN74ALS638A, SN74ALS639A, SN74AS638A, SN74AS639
OCTAL BUS TRANSCEIVERS
SDAS123A – DECEMBER 1983 – REVISED JANUARY 1995
•
•
•
•
DW OR N PACKAGE
(TOP VIEW)
Bidirectional Bus Transceivers in
High-Density 20-Pin Packages
Choice of True or Inverting Logic
A-Bus Outputs Are Open Collector;
B-Bus Outputs Are 3 State
Package Options Include Plastic
Small-Outline (DW) Packages and
Standard Plastic (N) 300-mil DIPs
A
OUTPUT
B
OUTPUT
LOGIC
SN74ALS638A, SN74AS638A
Open collector
3 state
Inverting
SN74ALS639A, SN74AS639
Open collector
3 state
True
DEVICE
DIR
A1
A2
A3
A4
A5
A6
A7
A8
GND
1
20
2
19
3
18
4
17
5
16
6
15
7
14
8
13
9
12
10
11
VCC
OE
B1
B2
B3
B4
B5
B6
B7
B8
description
These octal bus transceivers are designed for asynchronous two-way communication between open-collector
and 3-state buses. The devices transmit data from the A bus (open-collector) to the B bus (3 state) or from the
B bus to the A bus, depending on the logic level at the direction-control (DIR) input. The output-enable (OE) input
can be used to disable the device so the buses are isolated.
The -1 version of SN74ALS638A is identical to the standard version, except that the recommended maximum
IOL is increased to 48 mA.
The SN74ALS638A, SN74ALS639A, SN74AS638A, and SN74AS639 are characterized for operation from 0°C
to 70°C.
FUNCTION TABLE
INPUTS
OPERATION
DIR
SN74ALS638A
SN74AS638A
SN74ALS639A
SN74AS639
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
OE
Copyright 1995, Texas Instruments Incorporated
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.
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• DALLAS, TEXAS 75265
1
SN74ALS638A, SN74ALS639A, SN74AS638A, SN74AS639
OCTAL BUS TRANSCEIVERS
SDAS123A – DECEMBER 1983 – REVISED JANUARY 1995
logic symbols†
SN74ALS638A, SN74AS638A
OE
DIR
A1
19
1
2
SN74ALS639A, SN74AS639
G3
OE
3 EN1 [BA]
3 EN2 [AB]
DIR
18
1
B1
19
G3
1
A1
3 EN1 [BA]
3 EN2 [AB]
2
2
A2
A3
A4
A5
A6
A7
A8
18
1
B1
2
3
17
4
16
5
15
6
14
7
13
8
12
9
11
B2
A2
B3
A3
B4
A4
B5
A5
B6
A6
B7
B8
A7
A8
3
17
4
16
5
15
6
14
7
13
8
12
9
11
B2
B3
B4
B5
B6
B7
B8
† These symbols are in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.
logic diagrams (positive logic)
SN74ALS638A, SN74AS638A
OE
DIR
A1
SN74ALS639A, SN74AS639
19
OE
1
2
DIR
18
B1
A1
19
1
2
To Seven Other Transceivers
18
B1
To Seven Other Transceivers
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)‡
Supply voltage, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 V
Input voltage, VI: All inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 V
A-bus I/O ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 V
B-bus I/O ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.5 V
Operating free-air temperature range, TA: SN74ALS638A, SN74ALS639A . . . . . . . . . . . . . . . . . 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.
2
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SN74ALS638A, SN74ALS639A, SN74AS638A, SN74AS639
OCTAL BUS TRANSCEIVERS
SDAS123A – DECEMBER 1983 – REVISED JANUARY 1995
recommended operating conditions
SN74ALS638A
SN74ALS639A
UNIT
MIN
NOM
MAX
4.5
5
5.5
VCC
VIH
Supply voltage
VIL
VOH
Low-level input voltage
High-level output voltage
A ports
5.5
V
IOH
High-level output current
B ports
– 15
mA
IOL
Low level output current
Low-level
A or B ports
24
48†
mA
70
°C
High-level input voltage
2
V
0.8
TA
Operating free-air temperature
† Applies only to the SN74ALS638A-1 version and only if VCC is between 4.75 V and 5.25 V
V
0
V
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
PARAMETER
TEST CONDITIONS
SN74ALS638A
SN74ALS639A
MIN
VIK
IOH
A ports
VOH
B ports
VOL
II
A or B ports
Control inputs
A or B ports
VCC = 4.5 V,
VCC = 4.5 V,
II = – 18 mA
VOH = 5.5 V
VCC = 4.5 V to 5.5 V,
IOH = – 0.4 mA
IOH = – 3 mA
VCC = 4
4.5
5V
VCC = 4.5 V
IOH = – 15 mA
IOL = 12 mA
VI = 7 V
VI = 5.5 V
IIH
Control inputs
A or B ports§
VCC = 5
5.5
5V
V,
VI = 2
2.7
7V
IIL
Control inputs
A or B ports§
VCC = 5
5.5
5V
V,
VI = 0
0.4
4V
IO¶
B ports
VCC = 5.5 V,
VO = 2.25 V
Outputs high
SN74ALS638A
VCC = 5.5 V
ICC
SN74ALS639A
VCC = 5.5 V
UNIT
MAX
– 1.5
0.1
VCC – 2
2.4
V
mA
V
3.2
2
IOL = 24 mA
IOL = 48 mA†
VCC = 5
5.5
5V
TYP‡
0.25
0.4
0.35
0.5
0.35
0.5
0.1
0.1
20
20
– 0.1
– 0.1
– 30
– 112
18
30
Outputs low
26
41
Outputs disabled
16
30
Outputs high
25
40
Outputs low
30
50
Outputs disabled
33
V
mA
µA
mA
mA
mA
54
† Applies only to the SN74ALS638A-1 version and only if VCC is between 4.75 V and 5.25 V
‡ All typical values are at VCC = 5 V, TA = 25°C.
§ 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.
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
3
SN74ALS638A, SN74ALS639A, SN74AS638A, SN74AS639
OCTAL BUS TRANSCEIVERS
SDAS123A – DECEMBER 1983 – REVISED JANUARY 1995
switching characteristics (see Figure 1)
PARAMETER
FROM
(INPUT)
TO
(OUTPUT)
VCC = 4.5 V to 5.5 V,
CL = 50 pF,
RL = 680 Ω (A outputs),
R1 = R2 = 500 Ω (B outputs),
TA = MIN to MAX†
SN74ALS638A
tPLH
tPHL
A
B
tPLH
tPHL
B
A
tPLH
tPHL
OE
A
tPZH
tPZL
OE
B
tPHZ
tPLZ
OE
B
UNIT
SN74ALS639A
MIN
MAX
MIN
MAX
2
12
2
12
2
12
2
12
8
25
10
30
8
30
5
22
5
25
10
30
10
45
10
35
5
20
6
21
5
22
8
25
2
10
2
10
3
15
3
16
ns
ns
ns
ns
ns
† For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)‡
Supply voltage, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 V
Input voltage, VI: All inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 V
A-bus I/O ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 V
B-bus I/O ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.5 V
Operating free-air temperature range, TA: SN74AS638A, SN74AS639 . . . . . . . . . . . . . . . . . . . . 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
SN74AS638A
SN74AS639
UNIT
MIN
NOM
MAX
4.5
5
5.5
VCC
VIH
Supply voltage
VIL
VOH
Low-level input voltage
High-level output voltage
A ports
5.5
V
IOH
IOL
High-level output current
B ports
– 15
mA
Low-level output current
A or B ports
64
mA
TA
Operating free-air temperature
70
°C
4
High-level input voltage
2
V
0.8
0
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
V
V
SN74ALS638A, SN74ALS639A, SN74AS638A, SN74AS639
OCTAL BUS TRANSCEIVERS
SDAS123A – DECEMBER 1983 – REVISED JANUARY 1995
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
PARAMETER
SN74AS638A
SN74AS639
TEST CONDITIONS
MIN
VIK
IOH
A ports
VOH
B ports
VOL
A or B ports
II
VCC = 4.5 V,
VCC = 4.5 V,
II = – 18 mA
VOH = 5.5 V
VCC = 4.5 V to 5.5 V,
IOH = – 2 mA
IOH = – 3 mA
VCC – 2
2.4
IOH = – 15 mA
IOL = 64 mA
2.4
VCC = 4
4.5
5V
VCC = 4.5 V,
Control inputs
A or B ports
5V
VCC = 5
5.5
VI = 7 V
VI = 5.5 V
IIH
Control inputs
A or B ports‡
VCC = 5
5.5
5V
V,
VI = 2
2.7
7V
IIL
Control inputs
A or B ports‡
VCC = 5
5.5
5V
V,
VI = 0
0.4
4V
VCC = 5.5 V,
VO = 2.25 V
Outputs high
IO§
SN74AS638A
VCC = 5.5 V
ICC
SN74AS639
VCC = 5.5 V
TYP†
UNIT
MAX
– 1.2
0.1
0.55
0.1
0.1
20
70
– 0.5
– 0.75
– 50
mA
V
3.2
0.35
V
– 150
24
54
Outputs low
75
122
Outputs disabled
37
61
Outputs high
56
92
Outputs low
95
154
V
mA
µA
mA
mA
mA
Outputs disabled
62
100
† All typical values are at VCC = 5 V, TA = 25°C.
‡ 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.
switching characteristics (see Figure 1)
PARAMETER
FROM
(INPUT)
TO
(OUTPUT)
tPLH
tPHL
A
B
tPLH
tPHL
B
A
tPLH
tPHL
OE
A
tPZH
tPZL
OE
B
tPHZ
tPLZ
OE
B
VCC = 4.5 V to 5.5 V,
CL = 50 pF,
RL = 500 Ω (A outputs),
R1 = R2 = 500 Ω (B outputs),
TA = MIN to MAX¶
SN74AS638A
SN74AS639
MIN
MAX
MIN
MAX
2
7
2
9.5
2
6.5
2
9
5
20
5
22
2
7
2
9
5
19
5
21.5
2
9
2
11.5
2
8
2
10.5
2
10
2
10.5
2
7
2
7
2
10
2
10.5
UNIT
ns
ns
ns
ns
ns
¶ For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.
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5
SN74ALS638A, SN74ALS639A, SN74AS638A, SN74AS639
OCTAL BUS TRANSCEIVERS
SDAS123A – DECEMBER 1983 – REVISED JANUARY 1995
PARAMETER MEASUREMENT INFORMATION
SERIES 54ALS/74ALS AND 54AS/74AS DEVICES
7V
RL = R1 = R2
VCC
S1
RL
R1
Test
Point
From Output
Under Test
CL
(see Note A)
From Output
Under Test
RL
Test
Point
From Output
Under Test
CL
(see Note A)
CL
(see Note A)
LOAD CIRCUIT FOR
BI-STATE
TOTEM-POLE OUTPUTS
LOAD CIRCUIT
FOR OPEN-COLLECTOR OUTPUTS
3.5 V
Timing
Input
Test
Point
LOAD CIRCUIT
FOR 3-STATE OUTPUTS
3.5 V
High-Level
Pulse
1.3 V
R2
1.3 V
1.3 V
0.3 V
0.3 V
Data
Input
tw
th
tsu
3.5 V
1.3 V
3.5 V
Low-Level
Pulse
1.3 V
0.3 V
1.3 V
0.3 V
VOLTAGE WAVEFORMS
SETUP AND HOLD TIMES
VOLTAGE WAVEFORMS
PULSE DURATIONS
3.5 V
Output
Control
(low-level
enabling)
1.3 V
1.3 V
0.3 V
tPZL
Waveform 1
S1 Closed
(see Note B)
tPLZ
[3.5 V
1.3 V
tPHZ
tPZH
Waveform 2
S1 Open
(see Note B)
1.3 V
VOL
0.3 V
VOH
1.3 V
0.3 V
[0 V
3.5 V
1.3 V
Input
1.3 V
0.3 V
tPHL
tPLH
VOH
In-Phase
Output
1.3 V
1.3 V
VOL
tPLH
tPHL
VOH
Out-of-Phase
Output
(see Note C)
1.3 V
1.3 V
VOL
VOLTAGE WAVEFORMS
PROPAGATION DELAY TIMES
VOLTAGE WAVEFORMS
ENABLE AND DISABLE TIMES, 3-STATE OUTPUTS
NOTES: A. CL includes probe and jig capacitance.
B. Waveform 1 is for an output with internal conditions such that the output is low except when disabled by the output control.
Waveform 2 is for an output with internal conditions such that the output is high except when disabled by the output control.
C. When measuring propagation delay items of 3-state outputs, switch S1 is open.
D. All input pulses have the following characteristics: PRR ≤ 1 MHz, tr = tf = 2 ns, duty cycle = 50%.
E. The outputs are measured one at a time with one transition per measurement.
Figure 1. Load Circuits and Voltage Waveforms
6
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PACKAGE OPTION ADDENDUM
www.ti.com
10-Dec-2020
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
SN74ALS638AN
ACTIVE
PDIP
N
20
20
RoHS &
Non-Green
NIPDAU
N / A for Pkg Type
0 to 70
SN74ALS638AN
SN74ALS639ADW
ACTIVE
SOIC
DW
20
25
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
0 to 70
ALS639A
SN74ALS639AN
ACTIVE
PDIP
N
20
20
RoHS &
Non-Green
NIPDAU
N / A for Pkg Type
0 to 70
SN74ALS639AN
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of