74AC16646 Datasheet, PDF (1/10 Pages) Texas Instruments – 16-BIT BUS TRANSCEIVERS AND REGISTERS WITH 3-STATE OUTPUTS

54AC16646, 74AC16646
16ĆBIT BUS TRANSCEIVERS AND REGISTERS
WITH 3ĆSTATE OUTPUTS
SCAS241A − MARCH 1990 − REVISED APRIL 1996
D Members of the Texas Instruments
Widebust Family
D Independent Registers for A and B Buses
D Multiplexed Real-Time and Stored Data
D Flow-Through Architecture Optimizes
PCB Layout
D Distributed V_CC and GND Pin Configurations
Minimize High-Speed Switching Noise
D EPICt (Enhanced-Performance Implanted
CMOS) 1-mm Process
D 500-mA Typical Latch-Up Immunity at
125°C
D Package Options Include Plastic 300-mil
Shrink Small-Outline (DL) Packages Using
25-mil Center-to-Center Pin Spacings and
380-mil Fine-Pitch Ceramic Flat (WD)
Packages Using 25-mil Center-to-Center
Pin Spacings
description
The ’AC16646 are 16-bit bus transceivers that
consist of D-type flip-flops and control circuitry,
with 3-state outputs arranged for multiplexed
transmission of data directly from the data bus or
from the internal storage registers. The devices
can be used as two 8-bit transceivers or one 16-bit
transceiver. Data on the A or B bus is 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 bus transceivers and
registers.
54AC16646 . . . WD PACKAGE
74AC16646 . . . DL PACKAGE
(TOP VIEW)
1DIR 1
1CLKAB 2
1SAB 3
GND 4
1A1 5
1A2 6
V_CC 7
1A3 8
1A4 9
1A5 10
GND 11
1A6 12
1A7 13
1A8 14
2A1 15
2A2 16
2A3 17
GND 18
2A4 19
2A5 20
2A6 21
V_CC 22
2A7 23
2A8 24
GND 25
2SAB 26
2CLKAB 27
2DIR 28
56 1OE
55 1CLKBA
54 1SBA
53 GND
52 1B1
51 1B2
50 V_CC
49 1B3
48 1B4
47 1B5
46 GND
45 1B6
44 1B7
43 1B8
42 2B1
41 2B2
40 2B3
39 GND
38 2B4
37 2B5
36 2B6
35 V_CC
34 2B7
33 2B8
32 GND
31 2SBA
30 2CLKBA
29 2OE
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
controls (SAB and SBA) can multiplex stored and real-time (transparent mode) data. The circuitry used for
select control eliminates the typical decoding glitch that occurs in a multiplexer during the transition between
stored and real-time data. DIR determines which bus receives 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.
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 74AC16646 is packaged in the TI shrink small-outline package, which provides twice the functionality of
standard small-outline packages in the same printed-circuit-board area.
The 54AC16646 is characterized for operation over the full military temperature range of −55°C to 125°C. The
74AC16646 is characterized for operation from −40°C to 85°C.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
EPIC and Widebus are trademarks of Texas Instruments Incorporated.
UNLESS OTHERWISE NOTED this document contains PRODUCTION
DATA information 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  1996, Texas Instruments Incorporated
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