SN74ALS638A_16 Datasheet, PDF (1/16 Pages) Texas Instruments – OCTAL BUS TRANSCEIVERS

SN74ALS638A, SN74ALS639A, SN74AS638A, SN74AS639
OCTAL BUS TRANSCEIVERS
• 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
DEVICE
SN74ALS638A, SN74AS638A
SN74ALS639A, SN74AS639
A
OUTPUT
Open collector
Open collector
B
OUTPUT
3 state
3 state
LOGIC
Inverting
True
SDAS123A – DECEMBER 1983 – REVISED JANUARY 1995
DW OR N PACKAGE
(TOP VIEW)
DIR ₁
A1 ₂
A2 3
A3 4
A4 5
A5 6
A6 7
A7 8
A8 9
GND 10
20 ^V_CC
19 ^OE
18 B1
17 B2
16 B3
15 B4
14 B5
13 B6
12 B7
11 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
I_OL is increased to 48 mA.
The SN74ALS638A, SN74ALS639A, SN74AS638A, and SN74AS639 are characterized for operation from 0°C
to 70°C.
INPUTS
OE DIR
L
L
L
H
H
X
FUNCTION TABLE
OPERATION
SN74ALS638A
SN74AS638A
SN74ALS639A
SN74AS639
B data to A bus B data to A bus
A data to B bus A data to B bus
Isolation
Isolation
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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Copyright © 1995, Texas Instruments Incorporated
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