DM74ALS251 3-STATE 1-of-8 Line Data Selector/Multiplexer
April 1984
Revised April 2000
DM74ALS251
3-STATE 1-of-8 Line Data Selector/Multiplexer
General Description
This Data Selector/Multiplexer contains full on-chip decod-
ing to select one-of-eight data sources as a result of a
unique three-bit binary code at the Select inputs. Two com-
plementary outputs provide both inverting and non-invert-
ing buffer operation. An Output Control input is provided
which, when at the high level, places both outputs in the
high impedance OFF-State. In order to prevent bus access
conflicts, output disable times are shorter than output
enable times. The Select input buffers incorporate internal
overlap features to ensure that select input changes do not
cause invalid output transients.
Features
s
Advanced oxide-isolated, ion-implanted Schottky TTL
process
s
Switching performance is guaranteed over full tempera-
ture and V
CC
supply range
s
Pin and functional compatible with LS family counterpart
s
Improved output transient handling capability
s
Output control circuitry incorporates power-up 3-STATE
feature
Ordering Code:
Order Number
DM74ALS251M
DM74ALS251SJ
DM74ALS251N
Package Number
M16A
M16D
N16E
Package Description
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow
16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
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 鈥淴鈥?to the ordering code.
Connection Diagram
Function Table
Inputs
Select
C
X
L
L
L
L
H
H
H
H
B
X
L
L
H
H
L
L
H
H
A
X
L
H
L
H
L
H
L
H
Strobe
S
H
L
L
L
L
L
L
L
L
Y
Z
D
0
D
1
D
2
D
3
D
4
D
5
D
6
D
7
W
Z
D
0
D
1
D
2
D
3
D
4
D
5
D
6
D
7
Outputs
H
=
HIGH Level
L
=
LOW Level
X
=
Don't Care
Z
=
High Impedance (OFF)
D0 thru D7
=
The Level of the Respective D Input
漏 2000 Fairchild Semiconductor Corporation
DS006214
www.fairchildsemi.com
1
2
3
4
5
6
7
