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DM74AS257(2000) View Datasheet(PDF) - Fairchild Semiconductor

Part Name
Description
View to exact match
DM74AS257
(Rev.:2000)
Fairchild
Fairchild Semiconductor Fairchild
DM74AS257 Datasheet PDF : 6 Pages
1 2 3 4 5 6
September 1986
Revised March 2000
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.
Features
s Switching specifications at 50 pF
s Switching specifications guaranteed over full tempera-
ture and VCC range
s Advanced oxide-isolated, ion-implanted Schottky TTL
process
s Functionally and pin for pin compatible with Schottky,
low power Schottky, and advanced low power Schottky
TTL counterpart
s Improved AC performance over Schottky, low power
Schottky, and advanced low power Schottky counter-
parts
s 3-STATE buffer-type output drive bus lines directly
s Expand any data input point
s Multiplex dual data buses
s General four functions of two variables (one variable is
common)
s Source programmable counters
Ordering Code:
Order Number Package Number
Package Description
DM74AS257M
M16A
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow
DM74AS257N
N16E
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
DM74AS258M
M16A
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow
DM74AS258N
N16E
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
Connection Diagram
Function Table
INPUTS
OUTPUT
SELECT A
CONTROL
H
X
X
L
L
L
L
L
H
L
H
X
L
H
X
H = HIGH Level
L = LOW Level
X = Don't Care
Z = High Impedance (OFF)
OUTPUT Y
B AS257 AS258
X
Z
Z
X
L
H
X
H
L
L
L
H
H
H
L
© 2000 Fairchild Semiconductor Corporation DS006107
www.fairchildsemi.com
 

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