MC74AC257, MC74ACT257
Quad 2−Input Multiplexer
with 3−State Outputs
The MC74AC257/74ACT257 is a quad 2−input multiplexer with
3−state outputs. Four bits of data from two sources can be selected
using a Common Data Select input. The four outputs present the
selected data in true (noninverted) form. The outputs may be switched
to a high impedance state by placing a logic HIGH on the common
Output Enable (OE) input, allowing the outputs to interface directly
with bus−oriented systems.
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•
•
•
•
w
Multiplexer Expansion by Tying Outputs Together
Noninverting 3−State Outputs
Outputs Source/Sink 24 mA
′ACT257
Has TTL Compatible Inputs
These devices are available in Pb−free package(s). Specifications herein
apply to both standard and Pb−free devices. Please see our website at
www.onsemi.com for specific Pb−free orderable part numbers, or
contact your local ON Semiconductor sales office or representative.
V
CC
16
OE
15
I
0c
14
I
1c
13
Z
c
12
I
0d
11
I
1d
10
Z
d
9
16
1
DIP−16
N SUFFIX
CASE 648
16
1
SO−16
D SUFFIX
CASE 751B
16
1
TSSOP−16
DT SUFFIX
CASE 948F
16
1
S
2
I
0a
3
I
1a
4
Z
a
5
I
0b
6
I
1b
7
Z
b
8
GND
1
EIAJ−16
M SUFFIX
CASE 966
Figure 1. Pinout: 16−Lead Packages Conductors
(Top View)
ORDERING INFORMATION
Device
MC74AC257N
MC74ACT257N
MC74AC257D
MC74ACT257D
MC74AC257DR2
MC74ACT257DR2
MC74AC257DT
MC74ACT257DT
MC74AC257DTR2
MC74ACT257M
MC74AC257MEL
MC74ACT257MEL
Package
PDIP−16
PDIP−16
SOIC−16
SOIC−16
SOIC−16
SOIC−16
TSSOP−16
TSSOP−16
Shipping
25 Units/Rail
25 Units/Rail
48 Units/Rail
48 Units/Rail
2500 Tape & Reel
2500 Tape & Reel
96 Units/Rail
96 Units/Rail
TSSOP−16 2500 Tape & Reel
EIAJ−16
EIAJ−16
EIAJ−16
50 Units/Rail
2000 Tape & Reel
2000 Tape & Reel
MC74ACT257DTR2 TSSOP−16 2500 Tape & Reel
DEVICE MARKING INFORMATION
See general marking information in the device marking
section on page 8 of this data sheet.
©
Semiconductor Components Industries, LLC, 2006
March, 2006
−
Rev. 7
1
Publication Order Number:
MC74AC257/D
MC74AC257, MC74ACT257
PIN NAME
PIN
S
OE
I
0a
−I
0d
I
1a
−I
1d
Z
a
−Z
d
FUNCTION
Common Data Select Input
3−State Output Enable Input
Data Inputs from Source 0
Data Inputs from Source 1
3−State Multiplexer Outputs
TRUTH TABLE
Output
Enable
OE
H
L
L
L
L
H = HIGH Voltage Level
L = LOW Voltage Level
X = Immaterial
Z = High Impedance
Select
Input
S
X
H
H
L
L
Data
Inputs
I
0
X
X
X
L
H
I
1
X
L
H
X
X
Outputs
Z
Z
L
H
L
H
OE I
0a
I
1a
I
0b
I
1b
I
0c
I
1c
I
0d
I
1d
S
Z
a
Z
b
Z
c
Z
d
Figure 2. Logic Symbol
FUNCTIONAL DESCRIPTION
The MC74AC257/74ACT257 is a quad 2−input
multiplexer with 3−state outputs. It selects four bits of data
from two sources under control of a Common Data Select
input. When the Select input is LOW, the I
0x
inputs are
selected and when Select is HIGH, the I
1x
inputs are
selected. The data on the selected inputs appears at the
outputs in true (noninverted) form. The device is the logic
implementation of a 4−pole, 2−position switch where the
position of the switch is determined by the logic levels
supplied to the Select input. The logic equations for the
outputs are shown below:
Z
a
= OE
•
(I
1a
•
S+I
0a
•
S)
Z
b
= OE
•
(I
1b
•
S+I
0b
•
S)
Z
c
= OE
•
(I
1c
•
S+I
0c
•
S)
Z
d
= OE
•
(I
1d
•
S+I
0d
•
S)
When the Output Enable input (OE) is HIGH, the outputs
are forced to a high impedance state. If the outputs are tied
together, all but one device must be in the high impedance
state to avoid high currents that would exceed the maximum
ratings. Designers should ensure the Output Enable signals
to 3−state devices whose outputs are tied together are
designed so there is no overlap.
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2
MC74AC257, MC74ACT257
OE
I
0a
I
1a
I
0b
I
1b
I
0c
I
1c
I
0d
I
1d
S
Z
a
NOTE:
Z
b
Z
c
Z
d
This diagram is provided only for the understanding of logic operations
and should not be used to estimate propagation delays.
Figure 3. Logic Diagram
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3
MC74AC257, MC74ACT257
MAXIMUM RATINGS*
Symbol
V
CC
V
IN
V
OUT
I
IN
I
OUT
I
CC
T
stg
Parameter
DC Supply Voltage (Referenced to GND)
DC Input Voltage (Referenced to GND)
DC Output Voltage (Referenced to GND)
DC Input Current, per Pin
DC Output Sink/Source Current, per Pin
DC V
CC
or GND Current per Output Pin
Storage Temperature
Value
−0.5
to +7.0
−0.5
to V
CC
+0.5
−0.5
to V
CC
+0.5
±20
±50
±50
−65
to +150
Unit
V
V
V
mA
mA
mA
°C
*Maximum Ratings are those values beyond which damage to the device may occur. Functional operation should be restricted to the Recom-
mended Operating Conditions.
RECOMMENDED OPERATING CONDITIONS
Symbol
V
CC
V
IN
, V
OUT
t
r
, t
f
Supply Voltage
DC Input Voltage, Output Voltage (Ref. to GND)
Input Rise and Fall Time (Note 1)
′AC
Devices except Schmitt Inputs
Input Rise and Fall Time (Note 2)
′ACT
Devices except Schmitt Inputs
Junction Temperature (PDIP)
Operating Ambient Temperature Range
Output Current
−
High
Output Current
−
Low
V
CC
@ 3.0 V
V
CC
@ 4.5 V
V
CC
@ 5.5 V
V
CC
@ 4.5 V
V
CC
@ 5.5 V
Parameter
′AC
′ACT
Min
2.0
4.5
0
−
−
−
−
−
−
−40
−
−
Typ
5.0
5.0
−
150
40
25
10
8.0
−
25
−
−
Max
6.0
5.5
V
CC
−
−
−
−
−
140
85
−24
24
ns/V
°C
°C
mA
mA
ns/V
Unit
V
V
t
r
, t
f
T
J
T
A
I
OH
I
OL
1. 1. V
in
from 30% to 70% V
CC
; see individual Data Sheets for devices that differ from the typical input rise and fall times.
2. 2. V
in
from 0.8 V to 2.0 V; see individual Data Sheets for devices that differ from the typical input rise and fall times.
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4
MC74AC257, MC74ACT257
DC CHARACTERISTICS
74AC
Symbol
Parameter
V
CC
(V)
T
A
= +25°C
Typ
V
IH
Minimum High Level
Input Voltage
Maximum Low Level
Input Voltage
Minimum High Level
Output Voltage
3.0
4.5
5.5
3.0
4.5
5.5
3.0
4.5
5.5
3.0
4.5
5.5
V
OL
Maximum Low Level
Output Voltage
3.0
4.5
5.5
3.0
4.5
5.5
I
IN
I
OZ
Maximum Input
Leakage Current
Maximum
3−State
Current
†Minimum Dynamic
Output Current
Maximum Quiescent
Supply Current
5.5
1.5
2.25
2.75
1.5
2.25
2.75
2.99
4.49
5.49
−
−
−
0.002
0.001
0.001
−
−
−
−
74AC
T
A
=
−40°C
to
+85°C
Unit
Conditions
Guaranteed Limits
2.1
3.15
3.85
0.9
1.35
1.65
2.9
4.4
5.4
2.56
3.86
4.86
0.1
0.1
0.1
0.36
0.36
0.36
±0.1
2.1
3.15
3.85
0.9
1.35
1.65
2.9
4.4
5.4
2.46
3.76
4.76
0.1
0.1
0.1
0.44
0.44
0.44
±1.0
V
V
OUT
= 0.1 V
or V
CC
−
0.1 V
V
OUT
= 0.1 V
or V
CC
−
0.1 V
I
OUT
=
−50
mA
V
IL
V
V
OH
V
V
*V
IN
= V
IL
or V
IH
−12
mA
I
OH
−24
mA
−24
mA
I
OUT
= 50
mA
V
V
*V
IN
= V
IL
or V
IH
12 mA
I
OL
24 mA
24 mA
V
I
= V
CC
, GND
V
I
(OE) = V
IL
, V
IH
V
I
= V
CC
, GND
V
O
= V
CC
, GND
V
OLD
= 1.65 V Max
V
OHD
= 3.85 V Min
V
IN
= V
CC
or GND
mA
5.5
5.5
5.5
5.5
−
−
−
−
±0.5
−
−
8.0
±5.0
75
−75
80
mA
mA
mA
mA
I
OLD
I
OHD
I
CC
*All outputs loaded; thresholds on input associated with output under test.
†Maximum test duration 2.0 ms, one output loaded at a time.
NOTE: I
IN
and I
CC
@ 3.0 V are guaranteed to be less than or equal to the respective limit @ 5.5 V V
CC
.
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