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74F257A Quad 2-Input Multiplexer with 3-STATE Outputs
April 1988
Revised September 2000
74F257A
Quad 2-Input Multiplexer with 3-STATE Outputs
General Description
The 74F257A 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 (non-inverted) form. The
outputs may be switched to a high impedance state with a
HIGH on the common Output Enable (OE) input, allowing
the outputs to interface directly with bus-oriented systems.
Features
s
Multiplexer expansion by tying outputs together
s
Non-inverting 3-STATE outputs
s
Input clamp diodes limit high-speed termination effects
Ordering Code:
Order Number
74F257ASC
74F257ASJ
74F257APC
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 “X” to the ordering code.
Logic Symbols
Connection Diagram
IEEE/IEC
© 2000 Fairchild Semiconductor Corporation
DS009507
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74F257A
Unit Loading/Fan Out
Pin Names
S
OE
I
0a
–I
0d
I
1a
–I
1d
Z
a
–Z
d
Description
Common Data Select Input
3-STATE Output Enable Input (Active LOW)
Data Inputs from Source 0
Data Inputs from Source 1
3-STATE Multiplexer Outputs
U.L.
HIGH/LOW
1.0/1.0
1.0/1.0
1.0/1.0
1.0/1.0
150/40 (33.3)
Input I
IH
/I
IL
Output I
OH
/I
OL
20
µ
A/
−
0.6 mA
20
µ
A/
−
0.6 mA
20
µ
A/
−
0.6 mA
20
µ
A/
−
0.6 mA
−
3 mA/24 mA (20 mA)
Truth Table
Output
Enable
OE
H
L
L
L
L
H
=
HIGH Voltage Level
L
=
LOW Voltage Level
X
=
Immaterial
Z
=
High Impedance
Functional Description
Data
Output
Inputs
I
0
X
X
X
L
H
I
1
X
L
H
X
X
Z
Z
L
H
L
H
The 74F257A 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 (non-
inverted) 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 equation for the outputs is shown below:
Z
n
=
OE • (I
n
• S
+
I
on
• S)
When the Output Enable input (OE) is HIGH, the outputs
are forced to a high impedance OFF 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.
Select
Input
S
X
H
H
L
L
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.
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2
74F257A
Absolute Maximum Ratings
(Note 1)
Storage Temperature
Ambient Temperature under Bias
Junction Temperature under Bias
V
CC
Pin Potential to Ground Pin
Input Voltage (Note 2)
Input Current (Note 2)
Voltage Applied to Output
in HIGH State (with V
CC
=
0V)
Standard Output
3-STATE Output
Current Applied to Output
in LOW State (Max)
ESD Last Passing Voltage (Min)
twice the rated I
OL
(mA)
4000V
−
65
°
C to
+
150
°
C
−
55
°
C to
+
125
°
C
−
55
°
C to
+
150
°
C
−
0.5V to
+
7.0V
−
0.5V to
+
7.0V
−
30 mA to
+
5.0 mA
Recommended Operating
Conditions
Free Air Ambient Temperature
Supply Voltage
0
°
C to
+
70
°
C
+
4.5V to
+
5.5V
−
0.5V to V
CC
−
0.5V to
+
5.5V
Note 1:
Absolute maximum ratings are values beyond which the device
may be damaged or have its useful life impaired. Functional operation
under these conditions is not implied.
Note 2:
Either voltage limit or current limit is sufficient to protect inputs.
DC Electrical Characteristics
Symbol
V
IH
V
IL
V
CD
V
OH
Parameter
Input HIGH Voltage
Input LOW Voltage
Input Clamp Diode Voltage
Output HIGH
Voltage
10% V
CC
10% V
CC
5% V
CC
5% V
CC
V
OL
I
IH
I
BVI
I
CEX
V
ID
I
OD
I
IL
I
OZH
I
OZL
I
OS
I
ZZ
I
CCH
I
CCL
I
CCZ
Output LOW Voltage
Input HIGH
Current
Input HIGH Current
Breakdown Test
Output HIGH
Leakage Current
Input Leakage
Test
Output Leakage
Circuit Current
Input LOW Current
Output Leakage Current
Output Leakage Current
Output Short-Circuit Current
Bus Drainage Test
Power Supply Current
Power Supply Current
Power Supply Current
9.0
14.5
15
−60
4.75
3.75
−0.6
50
−50
−150
500
15
22
23
10% V
CC
2.5
2.4
2.7
2.7
0.5
5.0
7.0
50
V
µA
µA
µA
V
µA
mA
µA
µA
mA
µA
mA
mA
mA
Min
Max
Max
Max
0.0
0.0
Max
Max
Max
Max
0.0V
Max
Max
Max
V
Min
Min
2.0
0.8
−1.2
Typ
Max
Units
V
V
V
Min
V
CC
Conditions
Recognized as a HIGH Signal
Recognized as a LOW Signal
I
IN
= −18
mA
I
OH
= −1
mA
I
OH
= −3
mA
I
OH
= −1
mA
I
OH
= −3
mA
I
OL
=
24 mA
V
IN
=
2.7V
V
IN
=
7.0V
V
OUT
=
V
CC
I
ID
=
1.9
µA
All Other Pins Grounded
V
IOD
=
150 mV
All Other Pins Grounded
V
IN
=
0.5V
V
OUT
=
2.7V
V
OUT
=
0.5V
V
OUT
=
0V
V
OUT
=
5.25V
V
O
=
HIGH
V
O
=
LOW
V
O
=
HIGH Z
3
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74F257A
AC Electrical Characteristics
T
A
= +25°C
Symbol
Parameter
Min
t
PLH
t
PHL
t
PLH
t
PHL
t
PZH
t
PZL
t
PHZ
t
PLZ
Output Disable Time
Propagation Delay
I
n
to Z
n
Propagation Delay
S to Z
n
Output Enable Time
2.5
2.0
4.0
2.5
2.0
2.5
2.0
2.0
V
CC
=
5.0V
C
L
=
50 pF
Typ
4.5
4.2
5.0
6.5
5.9
5.5
4.3
4.5
Max
5.5
5.5
9.5
7.0
6.0
7.0
6.0
6.0
T
A
= −55°C
to
+125°C
V
CC
=
5.0V
C
L
=
50 pF
Min
2.0
1.5
3.5
2.5
2.0
2.5
2.0
2.0
Max
7.0
7.0
11.5
9.0
8.0
9.0
7.0
8.5
T
A
=
0°C to
+70°C
V
CC
=
5.0V
C
L
=
50 pF
Min
2.0
2.0
3.5
2.5
2.0
2.5
2.0
2.0
Max
6.0
6.0
10.5
8.0
7.0
8.0
7.0
7.0
ns
ns
ns
Units
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4
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