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DM74AS257, DM74AS258 3-STATE Quad 1 of 2 Line Data Selector/Multiplexers
May 2007
DM74AS257, DM74AS258
3-STATE Quad 1 of 2 Line Data Selector/Multiplexers
Features
■
Switching specifications at 50pF
■
Switching specifications guaranteed over full
■
■
tm
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 propa-
gation delay time.
This 3-STATE output feature means that n-bit (paral-
leled) data selectors with up to 300 sources can be
implemented for data buses. It also permits the use of
standard TTL registers for data retention throughout the
system.
■
■
■
■
■
■
temperature and V
CC
range
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
counterparts
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
Ordering Information
Order
Number
DM74AS257M
DM74AS257N
DM74AS258M
Package
Number
M16A
N16E
M16A
Package Description
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
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering number.
©1986 Fairchild Semiconductor Corporation
DM74AS257, DM74AS258 Rev. 1.2
www.fairchildsemi.com
DM74AS257, DM74AS258 3-STATE Quad 1 of 2 Line Data Selector/Multiplexers
Connection Diagram
Function Table
Inputs
OUTPUT
Control Select
H
L
L
L
L
H
=
HIGH Level
L
=
LOW Level
X
=
Don't Care
Z
=
High Impedance (OFF)
X
L
L
H
H
Output Y
A
X
L
H
X
X
B
X
X
X
L
H
AS257 AS258
Z
L
H
L
H
Z
H
L
H
L
Logic Diagrams
DM74AS257
DM74AS258
©1986 Fairchild Semiconductor Corporation
DM74AS257, DM74AS258 Rev. 1.2
www.fairchildsemi.com
2
DM74AS257, DM74AS258 3-STATE Quad 1 of 2 Line Data Selector/Multiplexers
Absolute Maximum Ratings
Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be
operable above the recommended operating conditions and stressing the parts to these levels is not recommended.
In addition, extended exposure to stresses above the recommended operating conditions may affect device reliability.
The absolute maximum ratings are stress ratings only.
Symbol
V
CC
V
I
T
A
T
STG
θ
JA
Supply Voltage
Input Voltage
Parameter
Rating
7V
7V
5.5V
0°C to +70°C
–65°C to +150°C
75.0°C/W
Voltage Applied to Disabled Output
Operating Free Air Temperature Range
Storage Temperature Range
Typical Thermal Resistance, N Package
Recommended Operating Conditions
The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended
operating conditions are specified to ensure optimal performance to the datasheet specifications. Fairchild does not
recommend exceeding them or designing to absolute maximum ratings.
Symbol
V
CC
V
IH
V
IL
I
OH
I
OL
T
A
Parameter
Supply Voltage
HIGH Level Input Voltage
LOW Level Input Voltage
HIGH Level Output Current
LOW Level Output Current
Free Air Operating Temperature
Min.
4.5
2
Nom.
5
Max.
5.5
0.8
–15
48
Units
V
V
V
mA
mA
°C
0
70
©1986 Fairchild Semiconductor Corporation
DM74AS257, DM74AS258 Rev. 1.2
www.fairchildsemi.com
3
DM74AS257, DM74AS258 3-STATE Quad 1 of 2 Line Data Selector/Multiplexers
Electrical Characteristics
Over recommended operating free air temperature range. All typical values are measured at V
CC
=
5V, T
A
=
25°C.
Symbol
V
IK
V
OH
V
OL
I
I
I
IH
I
IL
I
O(1)
I
OZH
I
OZL
I
CCH
I
CCL
I
CCZ
Parameter
Input Clamp Voltage
HIGH Level Output Voltage
LOW Level Output Voltage
Input Current @ Max. Input
Voltage
HIGH Level Input Current
LOW Level Input Current
Output Drive Current
Off-State Output Current,
HIGH Level Voltage Applied
Off-State Output Current,
LOW Level Voltage Applied
Supply Current DM74AS257
DM74AS258
Supply Current DM74AS257
DM74AS258
Supply Current DM74AS257
DM74AS258
Conditions
V
CC
=
4.5V, I
I
=
–18 mA
V
CC
=
4.5V, I
OH
=
Max
I
OH
=
–2 mA, V
CC
=
4.5V to 5.5V
V
CC
=
4.5V, I
OL
=
Max
V
CC
=
5.5V, V
IH
=
7V
A, B, G
Select
V
CC
=
5.5V, V
IH
=
2.7V A, B, G
Select
V
CC
=
5.5V, V
IL
=
0.4V
V
CC
=
5.5V, V
O
=
2.25V
V
CC
=
5.5V, V
O
=
2.7V
V
CC
=
5.5V, V
O
=
0.4V
V
CC
=
5.5V,
Outputs Open
Outputs HIGH
Outputs LOW
Outputs
Disabled
Select
All Others
Min.
2.4
V
CC
– 2
Typ.
3.2
0.35
Max.
–1.2
Units
V
V
0.5
0.1
0.2
20
40
–1
–0.5
V
mA
µA
mA
mA
µA
µA
mA
mA
mA
–30
–112
–50
–50
12.9
8.8
19
15.8
19.7
15.5
19.7
13.5
30.6
24.6
31.9
25.2
Note:
1. The output conditions have been chosen to produce a current that closely approximates one half of the true
short-circuit output current, I
OS
.
©1986 Fairchild Semiconductor Corporation
DM74AS257, DM74AS258 Rev. 1.2
www.fairchildsemi.com
4
