dm74as257 Fairchild Semiconductor, dm74as257 Datasheet

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dm74as257

Manufacturer Part Number
dm74as257
Description
3-state Quad 1 Of 2 Line Data Selector/multiplexers
Manufacturer
Fairchild Semiconductor
Datasheet

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© 2000 Fairchild Semiconductor Corporation
DM74AS257M
DM74AS257N
DM74AS258M
DM74AS258N
DM74AS257 • DM74AS258
3-STATE Quad 1 of 2 Line Data Selector/Multiplexers
General Description
These data selectors/multiplexers contain inverters and
drivers to supply full on-chip data selection to the four 3-
STATE outputs that can interface directly with data lines of
bus-organized systems. A 4-bit word selected from one of
two sources is routed to the four outputs. The DM74AS257
presents true data whereas the DM74AS258 presents
inverted data to minimize propagation delay time.
This 3-STATE output feature means that n-bit (paralleled)
data selectors with up to 300 sources can be implemented
for data buses. It also permits the use of standard TTL reg-
isters for data retention throughout the system.
Ordering Code:
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
Connection Diagram
Order Number
Package Number
M16A
M16A
N16E
N16E
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
DS006107
Features
Function Table
H
L
X
Z
CONTROL
OUTPUT
Switching specifications at 50 pF
Switching specifications guaranteed over full tempera-
ture and V
Advanced oxide-isolated, ion-implanted Schottky TTL
process
Functionally and pin for pin compatible with Schottky,
low power Schottky, and advanced low power Schottky
TTL counterpart
Improved AC performance over Schottky, low power
Schottky, and advanced low power Schottky counter-
parts
3-STATE buffer-type output drive bus lines directly
Expand any data input point
Multiplex dual data buses
General four functions of two variables (one variable is
common)
Source programmable counters
LOW Level
Don't Care
High Impedance (OFF)
HIGH Level
H
L
L
L
L
Package Description
CC
SELECT
range
INPUTS
X
H
H
L
L
A
H
X
X
X
L
September 1986
Revised March 2000
B
H
X
X
X
L
www.fairchildsemi.com
AS257
OUTPUT Y
H
H
Z
L
L
AS258
H
H
Z
L
L

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dm74as257 Summary of contents

Page 1

... STATE outputs that can interface directly with data lines of bus-organized systems. A 4-bit word selected from one of two sources is routed to the four outputs. The DM74AS257 presents true data whereas the DM74AS258 presents inverted data to minimize propagation delay time. ...

Page 2

... Logic Diagrams DM74AS257 www.fairchildsemi.com DM74AS258 2 ...

Page 3

... CCL CC Current DM74AS258 Outputs Open I Supply DM74AS257 CCZ Current DM74AS258 Note 2: The output conditions have been chosen to produce a current that closely approximates one half of the true short-circuit output current, I (Note Note 1: The “Absolute Maximum Ratings” are those values beyond which 5 ...

Page 4

... DM74AS257 Switching Characteristics over recommended operating free air temperature range Symbol Parameter t Propagation Delay Time, PLH LOW-to-HIGH Level Output t Propagation Delay Time, PHL HIGH-to-LOW Level Output t Propagation Delay Time, PLH LOW-to-HIGH Level Output t Propagation Delay Time, PHL HIGH-to-LOW Level Output ...

Page 5

Physical Dimensions inches (millimeters) unless otherwise noted 16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow Package Number M16A 5 www.fairchildsemi.com ...

Page 6

Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide Fairchild does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and Fairchild reserves the right ...

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