MC74F257A [MOTOROLA]
QUAD 2-INPUT MULTIPLEXER WITH 3-STATE OUTPUTS; 四2输入多路复用器与3态输出
| 型号： | MC74F257A |
| 厂家： | 
MOTOROLA |
| 描述： | QUAD 2-INPUT MULTIPLEXER WITH 3-STATE OUTPUTS |
| 文件： | 总3页 (文件大小：67K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
MC74F257A
QUAD 2-INPUT MULTIPLEXER
WITH 3-STATE OUTPUTS
The MC74F257 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 com-
mon Output Enable (OE) input, allowing the outputs to interface directly with
bus oriented systems.
QUAD 2-INPUT MULTIPLEXER
WITH 3-STATE OUTPUTS
FAST SCHOTTKY TTL
• Multiplexer Expansion by Tying Outputs Together
• Non-Inverting 3-State Outputs
• Input Clamp Diodes Limit High-Speed Termination Effects
• AC Enhanced Version of the F257
J SUFFIX
CERAMIC
CASE 620-09
CONNECTION DIAGRAM
Z
9
V
OE
15
I
I
Z
I
I
d
CC
0c
1c
c
0d
1d
16
1
16
14
13
12
11
10
N SUFFIX
PLASTIC
CASE 648-08
16
1
2
3
4
5
6
7
8
1
GND
S
I
I
Z
I
I
Z
b
0a
1a
a
0b
1b
LOGIC DIAGRAM
D SUFFIX
SOIC
CASE 751B-03
OE
I
I
I
I
I
I
I
I
1d
S
0a
1a
0b
1b
0c
1c
0d
16
1
ORDERING INFORMATION
MC54FXXXAJ Ceramic
MC74FXXXAN Plastic
MC74FXXXAD SOIC
LOGIC SYMBOL
1
S
Z
Z
Z
Z
d
a
b
c
15
OE
4
Z
I
2
a
0a
FUNCTION TABLE
I
1a
3
Output
Enable
Select
Input
Data
Inputs
I
I
5
7
Z
Z
0b
1b
Outputs
b
c
6
OE
H
L
S
X
H
H
L
I
I
1
Z
Z
L
0
12
I
14
0c
X
X
X
L
X
L
13
11
10
I
I
I
1c
0d
1d
Z
9
d
L
H
X
X
H
L
H = HIGH Voltage Level
L = LOW Voltage Level
X = Don’t Care
V
= PIN 16
CC
GND = PIN 8
L
L
L
H
H
Z = High Impedance
FAST AND LS TTL DATA
4-127
MC74F257A
GUARANTEED OPERATING RANGES
Symbol
Parameter
Min
4.5
0
Typ
5.0
25
Max
5.5
70
Unit
V
V
CC
Supply Voltage
74
74
74
74
T
A
Operating Ambient Temperature Range
Output Current — High
Output Current — Low
°C
I
I
–3.0
24
mA
mA
OH
OL
DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE (unless otherwise specified)
Limits
Symbol
Parameter
Input HIGH Voltage
Min
Typ
Max
Unit
V
Test Conditions
Guaranteed Input HIGH Voltage
Guaranteed Input LOW Voltage
V
IH
2.0
V
V
V
Input LOW Voltage
0.8
V
IL
Input Clamp Diode Voltage
Output HIGH Voltage
–1.2
V
I
I
I
I
= –18 mA
V
V
V
V
V
V
V
= MIN
IK
IN
CC
CC
CC
CC
CC
CC
CC
74
74
2.4
2.7
3.3
3.3
V
= –3.0 mA
= –3.0 mA
= 24 mA
= 4.50 V
= 4.75 V
= MIN
OH
OH
OH
OL
V
V
Output LOW Voltage
0.35
0.5
50
V
OL
OZH
OZL
IH
I
I
I
Output OFF Current — HIGH
Output OFF Current — LOW
Input HIGH Current
µA
µA
µA
V
V
V
V
V
V
= 2.7 V
= 0.5 V
= MAX
= MAX
= MAX
OUT
–50
20
OUT
= 2.7 V
IN
100
–0.6
–150
15
= 7.0 V
IN
I
I
I
Input LOW Current
mA
mA
= 0.5 V
V
V
= MAX
= MAX
IL
IN
CC
Output Short Circuit Current (Note 2)
–60
= 0 V
OUT
OS
CCH
CC
9.0
14.5
15
S, I = 4.5 V
1x
OE, I = GND
0x
I
Power Supply Current
22
23
mA
I
1x
= 4.5 V
V
CC
= MAX
CCL
CCZ
OE, I
S = GND
0x,
I
S, I = GND
0x
OE, I = 4.5 V
1x
NOTES:
1. For conditions shown as MIN or MAX, use the appropriate value specified under guaranteed operating ranges.
2. Not more than one output should be shorted at a time, nor for more than 1 second.
FUNCTIONAL DESCRIPTION
The F257A is a quad 2-input multiplexer with 3-state out-
puts. It selects four bits of data from two sources under control
of a Common Data Select input. When the Select input is
Z = OE • (I • S + I • S)
a 1a 0a
Z = OE • (I • S + I • S)
1b 0b
b
Z = OE • (I • S + I • S)
1c 0c
c
LOW, theI inputsareselectedandwhenSelectisHIGH, the
Zd = OE • (I • S + I • S)
1d 0d
0x
I
1x
inputs are selected. The data on the selected inputs ap-
WhentheOutputEnableinput(OE)isHIGH, theoutputsare
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.
pears at the outputs in true (non-inverted) form. The device is
the logic implementation of a 4-pole, 2-position switch where
theposition of the switch is determined by the logic levels sup-
pliedtotheSelectinput.Thelogicequationsfortheoutputsare
shown below:
FAST AND LS TTL DATA
4-128
MC74F257A
AC CHARACTERISTICS
74F
74F
T
A
= +25°C
T
A
= 0°C to 70°C
V
= +5.0 V
= 50 pF
V
CC
= 5.0 V ± 10%
CC
C
C = 50 pF
L
L
Symbol
Parameter
Min
Max
Min
1.5
2.0
3.0
2.5
2.0
2.5
2.0
2.0
Max
Unit
t
t
t
t
t
t
t
t
Propagation Delay
to Z
1.5
2.0
3.0
2.5
2.0
2.5
2.0
2.0
5.5
5.5
9.5
7.0
6.5
7.0
6.0
6.0
6.0
6.0
10.5
8.0
7.0
8.0
7.0
7.0
ns
PLH
PHL
PLH
PHL
PZH
PZL
PHZ
PLZ
I
n
n
Propagation Delay
S to Z
ns
ns
ns
n
Output Enable Time
Output Disable Time
FAST AND LS TTL DATA
4-129
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