SN74HCT646 Datasheet, PDF (1/11 Pages) Texas Instruments – OCTAL BUS TRANSCEIVERS AND REGISTERS WITH 3-STATE OUTPUTS

D Operating Voltage Range of 4.5 V to 5.5 V
D Low Power Consumption, 80-µA Max I_CC
D Typical t_pd = 12 ns
D ±6-mA Output Drive at 5 V
D Low Input Current of 1 µA Max
D Inputs Are TTL-Voltage Compatible
SN54HCT646 . . . JT OR W PACKAGE
SN74HCT646 . . . DW OR NT PACKAGE
(TOP VIEW)
SN54HCT646, SN74HCT646
OCTAL BUS TRANSCEIVERS AND REGISTERS
WITH 3-STATE OUTPUTS
SCLS178C – MARCH 1984 – REVISED MARCH 2003
D Independent Registers for A and B Buses
D Multiplexed Real-Time and Stored Data
D True Data Paths
D High-Current 3-State Outputs Can Drive Up
To 15 LSTTL Loads
SN54HCT646 . . . FK 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
4 3 2 1 28 27 26
A1 ₅
25 ^OE
A2 ₆
24 B1
A3 7
23 B2
NC 8
22 NC
A4 9
21 B3
A5 10
20 B4
A6 1112 _{13 14 15 16 17 1819} B5
description/ordering information
NC – No internal connection
The ’HCT646 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 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 ’HCT646 devices.
Output-enable (OE) and direction-control (DIR) inputs control the transceiver functions. In the transceiver
mode, data present at the high-impedance port can be stored in either or both registers.
ORDERING INFORMATION
TA
PACKAGE†
ORDERABLE
PART NUMBER
TOP-SIDE
MARKING
PDIP – NT
Tube
SN74HCT646NT
SN74HCT646NT
–40°C to 85°C
SOIC – DW
Tube
Tape and reel
SN74HCT646DW
SN74HCT646DWR
HCT646
CDIP – JT
Tube
SNJ54HCT646JT
SNJ54HCT646JT
–55°C to 125°C CFP – W
Tube
SNJ54HCT646W
SNJ54HCT646W
LCCC – FK
Tube
SNJ54HCT646FK
SNJ54HCT646FK
† _{Package drawings, standard packing quantities, thermal data, symbolization, and PCB design guidelines are}
available at www.ti.com/sc/package.
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.
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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