Datasheet

 
     
  
SCLS072D − NOVEMBER 1988 − REVISED SEPTEMBER 2003
1
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
D Operating Voltage Range of 4.5 V to 5.5 V
D High-Current 3-State Outputs Interface
Directly With System Bus
D Typical t
pd
= 17 ns
D Low Power Consumption, 80-µA Max I
CC
D ±6-mA Output Drive at 5 V
D Low Input Current of 1 µA Max
D Inputs Are TTL-Voltage Compatible
D Provide Bus Interface From Multiple
Sources in High-Performance Systems
D Buffered Inputs and Outputs
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
A/B
1A
1B
1Y
2A
2B
2Y
GND
V
CC
OE
4A
4B
4Y
3A
3B
3Y
SN54HCT257 ... J PACKAGE
SN74HCT257 ...D OR N PACKAGE
(TOP VIEW)
3212019
910111213
4
5
6
7
8
18
17
16
15
14
4A
4B
NC
4Y
3A
1B
1Y
NC
2A
2B
1A A/B NC
3Y 3B
V OE
2Y
GND
NC
SN54HCT257 . . . FK PACKAGE
(TOP VIEW)
CC
NC − No internal connection
description/ordering information
The ’HCT257 devices are designed to multiplex signals from 4-bit data sources to 4-output data lines in
bus-organized systems. The 3-state outputs do not load the data lines when the output-enable (OE
) input is at
the high logic level.
To ensure the high-impedance state during power up or power down, OE
should be tied to V
CC
through a pullup
resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.
ORDERING INFORMATION
T
A
PACKAGE
†
ORDERABLE
PART NUMBER
TOP-SIDE
MARKING
PDIP − N Tube of 25 SN74HCT257N SN74HCT257N
−40°C to 85°C
Tube of 40 SN74HCT257D
−40°C to 85°C
SOIC − D
Reel of 2500 SN74HCT257DR
HCT257
SOIC − D
Reel of 250 SN74HCT257DT
HCT257
−55°C to 125°C
CDIP − J Tube of 25 SNJ54HCT257J SNJ54HCT257J
−55°C to 125°C
LCCC − FK Tube of 55 SNJ54HCT257FK SNJ54HCT257FK
†
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 o
f
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
Copyright  2003, Texas Instruments Incorporated
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