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Электронный компонент: 74ACT257SC

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1999 Fairchild Semiconductor Corporation
DS009949
www.fairchildsemi.com
November 1988
Revised November 1999
7
4
AC
2
57
74ACT257 Q
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a
d

2-
Input
M
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i
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3-
ST
A
T
E Output
s
74AC257 74ACT257
Quad 2-Input Multiplexer with 3-STATE Outputs
General Description
The AC/ACT257 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 out-
puts 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-ori-
ented systems.
Features
s
I
CC
and I
OZ
reduced by 50%
s
Multiplexer expansion by tying outputs together
s
Noninverting 3-STATE outputs
s
Outputs source/sink 24 mA
s
ACT257 has TTL-compatible inputs
Ordering Code:
Device also available in Tape and Reel. Specify by appending suffix letter "X" to the ordering code.
Logic Symbols
IEEE/IEC
Connection Diagram
Pin Descriptions
FACT
is a trademark of Fairchild Semiconductor Corporation.
Order Number
Package Number
Package Description
74AC257SC
M16A
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150" Narrow Body
74AC257SJ
M16D
16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
74AC257MTC
MTC16
16-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide
74AC257PC
N16E
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" Wide
74ACT257SC
M16A
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150" Narrow Body
74ACT257SJ
M16D
16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
74ACT257MTC
MTC16
16-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide
74ACT257PC
N16E
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" Wide
Pin Names
Description
S
Common Data Select Input
OE
3-STATE Output Enable Input
I
0a
I
0d
Data Inputs from Source 0
I
1a
I
1d
Data Inputs from Source 1
Z
a
Z
d
3-STATE Multiplexer Outputs
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2
74AC257

74ACT257
Functional Description
The AC/ACT257 is 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 deter-
mined by the logic levels supplied to the Select input. The
logic equations for the outputs are as follows:
Z
a
=
OE (1
1a
S
+
I
0a
S)
Z
b
=
OE (1
1b
S
+
I
0b
S)
Z
c
=
OE (1
1c
S
+
I
0c
S)
Z
d
=
OE (1
1d
S
+
I
0d
S)
When the Output Enable (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 maxi-
mum ratings. Designers should ensure the Output Enable
signals to 3-STATE devices whose outputs are tied
together are designed so there is no overlap.
Truth Table
H
=
HIGH Voltage Level
L
=
LOW Voltage Level
X
=
Immaterial
Z
=
High Impedance
Logic Diagram
Please note that this diagram is provided only for the understanding of logic operations and should not be used to estimate propagation delays.
Output
Select
Data
Outputs
Enable
Input
Inputs
OE
S
I
0
I
1
Z
H
X
X
X
Z
L
H
X
L
L
L
H
X
H
H
L
L
L
X
L
L
L
H
X
H
3
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74
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7


74ACT257
Absolute Maximum Ratings
(Note 1)
Recommended Operating
Conditions
Note 1: Absolute maximum ratings are those values beyond which damage
to the device may occur. The databook specifications should be met, with-
out exception, to ensure that the system design is reliable over its power
supply, temperature, and output/input loading variables. Fairchild does not
recommend operation of FACT
circuits outside databook specifications.
DC Electrical Characteristics for AC
Note 2: All outputs loaded; thresholds on input associated with output under test.
Note 3: Maximum test duration 2.0 ms, one output loaded at a time.
Note 4: I
IN
and I
CC
@ 3.0V are guaranteed to be less than or equal to the respective limit @ 5.5V V
CC
.
Supply Voltage (V
CC
)
-
0.5V to
+
7.0V
DC Input Diode Current (I
IK
)
V
I
=
-
0.5V
-
20 mA
V
I
=
V
CC
+
0.5V
+
20 mA
DC Input Voltage (V
I
)
-
0.5V to V
CC
+
0.5V
DC Output Diode Current (I
OK
)
V
O
=
-
0.5V
-
20 mA
V
O
=
V
CC
+
0.5V
+
20 mA
DC Output Voltage (V
O
)
-
0.5V to V
CC
+
0.5V
DC Output Source ort
Sink Curren (I
O
)
50 mA
DC V
CC
or Ground Current
Per Output Pin (I
CC
or I
GND
)
50 mA
Storage Temperature (T
STG
)
-
65
C to
+
150
C
Junction Temperature (T
J
)
PDIP
140
C
Supply Voltage (V
CC
)
AC
2.0V to 6.0V
ACT
4.5V to 5.5V
Input Voltage (V
I
)
0V to V
CC
Output Voltage (V
O
)
0V to V
CC
Operating Temperature (T
A
)
-
40
C to
+
85
C
Minimum Input Edge Rate (
V/
t)
AC Devices
V
IN
from 30% to 70% of V
CC
V
CC
@ 3.3V, 4.5V, 5.5V
125 mV/ns
Minimum Input Edge Rate (
V/
t)
ACT Devices
V
IN
from 0.8V to 2.0V
V
CC
@ 4.5V, 5.5V
125 mV/ns
Symbol
Parameter
V
CC
T
A
=
+
25
C
T
A
=
-
40
C to
+
85
C
Units
Conditions
(V)
Typ
Guaranteed Limits
V
IH
Minimum HIGH Level
3.0
1.5
2.1
2.1
V
OUT
=
0.1V
Voltage Input
4.5
2.25
3.15
3.15
V
or V
CC
-
0.1V
5.5
2.75
3.85
3.85
V
IL
Maximum LOW Level
3.0
1.5
0.9
0.9
V
OUT
=
0.1V
Voltage Input
4.5
2.25
1.35
1.35
V
or V
CC
-
0.1V
5.5
2.75
1.65
1.65
V
OH
Minimum HIGH Level
3.0
2.99
2.9
2.9
Voltage Output
4.5
4.49
4.4
4.4
V
I
OUT
=
-
50
A
5.5
5.49
5.4
5.4
V
IN
=
V
IL
or V
IH
3.0
2.56
2.46
I
OH
=
-
12 mA
4.5
3.86
3.76
V
I
OH
=
-
24 mA
5.5
4.86
4.76
I
OH
=
-
24 mA (Note 2)
V
OL
Maximum LOW Level
3.0
0.002
0.1
0.1
Voltage Output
4.5
0.001
0.1
0.1
V
I
OUT
=
50
A
5.5
0.001
0.1
0.1
V
IN
=
V
IL
or V
IH
3.0
0.36
0.44
I
OL
=
12 mA
4.5
0.36
0.44
V
I
OL
=
24 mA
5.5
0.36
0.44
I
OL
=
24 mA (Note 2)
I
IN
(Note 4)
Maximum Input Leakage Current
5.5
0.1
1.0
A
V
I
=
V
CC
, GND
I
OZ
Maximum 3-STATE
V
I
(OE)
=
V
IL
, V
IH
Leakage Current
5.5
0.25
2.5
A
V
I
=
V
CC
, GND
V
O
=
V
CC
, GND
I
OLD
Minimum Dynamic (Note 3)
5.5
75
mA
V
OLD
=
1.65V Max
I
OHD
Output Current
5.5
-
75
mA
V
OHD
=
3.85V Min
I
CC
(Note 4)
Maximum Quiescent Supply Current
5.5
4.0
40.0
A
V
IN
=
V
CC
or GND
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4
74AC257

74ACT257
DC Electrical Characteristics for ACT
Note 5: All outputs loaded; thresholds on input associated with output under test.
Note 6: Maximum test duration 2.0 ms, one output loaded at a time.
AC Electrical Characteristics for AC
Note 7: Voltage Range 3.3 is 3.0V
0.3V
Voltage Range 5.0 is 5.0V
0.5V
Symbol
Parameter
V
CC
T
A
=
+
25
C
T
A
=
-
40
C to
+
85
C
Units
Conditions
(V)
Typ
Guaranteed Limits
V
IH
Minimum HIGH Level
4.5
1.5
2.0
2.0
V
V
OUT
=
0.1V
Input Voltage
5.5
1.5
2.0
2.0
or V
CC
-
0.1V
V
IL
Maximum LOW Level
4.5
1.5
0.8
0.8
V
V
OUT
=
0.1V
Input Voltage
5.5
1.5
0.8
0.8
or V
CC
-
0.1V
V
OH
Minimum HIGH Level
4.5
4.49
4.4
4.4
V
I
OUT
=
-
50
A
Output Voltage
5.5
5.49
5.4
5.4
V
IN
=
V
IL
or V
IH
4.5
3.86
3.76
V
I
OH
=
-
24 mA
5.5
4.86
4.76
I
OH
=
-
24 mA (Note 5)
V
OL
Maximum LOW Level
4.5
0.001
0.1
0.1
V
I
OUT
=
50
A
Output Voltage
5.5
0.001
0.1
0.1
V
IN
=
V
IL
or V
IH
4.5
0.36
0.44
V
I
OL
=
24 mA
5.5
0.36
0.44
I
OL
=
24 mA (Note 5)
I
IN
Maximum Input
5.5
0.1
1.0
A
V
I
=
V
CC
, GND
Leakage Current
I
OZ
Maximum 3-STATE
5.5
0.5
5.0
A
V
I
=
V
IL
, V
IH
Leakage Current
V
O
=
V
CC
, GND
I
CCT
Maximum
5.5
0.6
1.5
mA
V
I
=
V
CC
-
2.1V
I
CC
/Input
I
OLD
Dynamic Output Current
5.5
75
mA
V
OLD
=
1.65V Max
I
OHD
Minimum (Note 6)
5.5
-
75
mA
V
OHD
=
3.85V Min
I
CC
Maximum Quiescent
5.5
4.0
40.0
A
V
IN
=
V
CC
Supply Current
or GND
V
CC
T
A
=
+
25
C
T
A
=
-
40
C to
+
85
C
Symbol
Parameter
(V)
C
L
=
50 pF
C
L
=
50 pF
Units
(Note 7)
Min
Typ
Max
Min
Max
t
PLH
Propagation Delay
3.3
1.5
5.0
8.5
1.0
9.0
ns
I
n
to Z
n
5.0
1.5
4.0
6.0
1.0
7.0
t
PHL
Propagation Delay
3.3
1.5
6.0
8.5
1.0
9.0
ns
I
n
to Z
n
5.0
1.5
4.5
6.0
1.0
7.0
t
PLH
Propagation Delay
3.3
1.5
7.0
10.5
1.5
11.5
ns
S to Z
n
5.0
1.5
5.0
7.5
1.0
8.5
t
PHL
Propagation Delay
3.3
1.5
7.5
10.5
1.5
11.5
ns
S to Z
n
5.0
1.5
5.5
7.5
1.0
8.5
t
PZH
Output Enable Time
3.3
1.5
6.5
9.5
1.0
10.5
ns
5.0
1.5
5.0
7.5
1.0
8.5
t
PZL
Output Enable Time
3.3
1.5
5.5
9.0
1.0
10.0
ns
5.0
1.5
5.0
8.5
1.0
9.5
t
PHZ
Output Disable Time
3.3
1.5
5.5
10.0
1.0
11.0
ns
5.0
1.5
5.0
9.0
1.0
10.0
t
PLZ
Output Disable Time
3.3
1.5
5.5
9.0
1.0
10.0
ns
5.0
1.5
5.0
8.0
1.0
9.0
5
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74
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74ACT257
AC Electrical Characteristics for ACT
Note 8: Voltage Range 5.0 is 5.0V
0.5V
Capacitance
V
CC
T
A
=
+
25
C
T
A
=
-
40
C to
+
85
C
Symbol
Parameter
(V)
C
L
=
50 pF
C
L
=
50 pF
Units
(Note 8)
Min
Typ
Max
Min
Max
t
PLH
Propagation Delay
5.0
1.5
5.0
7.0
1.0
7.5
ns
I
n
to Z
n
t
PHL
Propagation Delay
5.0
2.0
6.0
7.5
1.5
8.5
ns
I
n
to Z
n
t
PLH
Propagation Delay
5.0
2.0
7.0
9.5
1.5
10.5
ns
S to Z
n
t
PHL
Propagation Delay
5.0
2.5
7.0
10.5
2.0
11.5
ns
S to Z
n
t
PZH
Output Enable Time
5.0
2.0
6.0
8.0
1.5
9.0
ns
t
PZL
Output Enable Time
5.0
2.0
6.0
8.0
1.5
9.0
ns
t
PHZ
Output Disable Time
5.0
2.5
6.5
9.0
1.5
10.0
ns
t
PLZ
Output Disable Time
5.0
2.0
6.0
7.5
1.5
8.5
ns
Symbol
Parameter
Typ
Units
Conditions
C
IN
Input Capacitance
4.5
pF
V
CC
=
OPEN
C
PD
Power Dissipation Capacitance
50.0
pF
V
CC
=
5.0V