SN74BCT648 Datasheet, PDF (1/8 Pages) Texas Instruments – OCTAL BUS TRANSCEIVERS AND REGISTERS WITH 3-STATE OUTPUTS

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SN54BCT648, SN74BCT648
OCTAL BUS TRANSCEIVERS AND REGISTERS
WITH 3ĆSTATE OUTPUTS
SCBS050B − MAY 1990 − REVISED APRIL 1994
• State-of-the-Art BiCMOS Design
Significantly Reduces I_CCZ
• Independent Registers for A and B Buses
• Multiplexed Real-Time and Stored Data
• Inverting Data Paths
• Power-Up High-Impedance Mode
• Package Options Include Plastic
Small-Outline (DW) Packages, Ceramic
Chip Carriers (FK) and Flatpacks (W), and
Standard Plastic and Ceramic 300-mil DIPS
(JT, NT)
description
These devices consist of bus transceiver circuits
with 3-state outputs, D-type flip-flops, and control
circuitry arranged for multiplexed transmission of
data directly from the input bus or from the internal
registers. Data on the A or B bus will be clocked
into the registers on the low-to-high transition of
the appropriate clock (CLKAB or CLKBA) input.
Figure 1 illustrates the four fundamental bus-
management functions that can be performed with
the ′BCT648.
Output-enable (OE) and direction-control (DIR)
inputs are provided to control the transceiver
functions. In the transceiver mode, data present at
the high-impedance port may be stored in either
register or in both. The select control (SAB and
SBA) can multiplex stored and real-time
(transparent mode) data. The direction control
determines which bus will receive data when OE
is active (low). In the isolation mode (OE high), A
data may be stored in one register and/or B data
may be stored in the other register.
SN54BCT648 . . . JT OR W PACKAGE
SN74BCT648 . . . DW OR NT PACKAGE
(TOP VIEW)
CLKAB 1
SAB 2
DIR 3
A1 4
A2 5
A3 6
A4 7
A5 8
A6 9
A7 10
A8 11
GND 12
24 V_CC
23 CLKBA
22 SBA
21 OE
20 B1
19 B2
18 B3
17 B4
16 B5
15 B6
14 B7
13 B8
SN54BCT648 . . . FK PACKAGE
(TOP VIEW)
4 3 2 1 28 27 26
5
25 OE
6
24 B1
A1 7
23 B2
A2 8
22 NC
A3 9
21 B3
NC 10
20 _B4
A4 ¹¹¹² _{13 14 15 16 17 1819} B5
A5
A6
NC − No internal connection
When an output function is disabled, the input function is still enabled and may be used to store and transmit
data. Only one of the two buses, A or B, may be driven at a time.
The SN54BCT648 is characterized for operation over the full military temperature range of −55°C to 125°C. The
SN74BCT648 is characterized for operation from 0°C to 70°C.
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.
Copyright  1994, Texas Instruments Incorporated
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