MC54F251J データシートの表示（PDF） - Motorola => Freescale
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MC54F251J Datasheet PDF : 3 Pages
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8-INPUT MULTIPLEXER
WITH 3-STATE OUTPUTS
The MC54/74F251 is a high-speed 8-input digital multiplexer. It provides,
in one package, the ability to select one bit of data from up to eight sources.
It can be used as a universal function generator to generate any logic function
of four variables. Both assertion and negation outputs are provided.
• Multifunctional Capacity
• On-Chip Select Logic Decoding
• Inverting and Noninverting 3-State Outputs
FUNCTIONAL DESCRIPTION
This device is a logical implementation of a single-pole, 8-position switch
with the switch position controlled by the state of three Select inputs, S0, S1,
S2. Both assertion and negation outputs are provided. The Output Enable in-
put (OE) is active LOW. When it is activated, the logic function provided at the
output is:
Z = OE • (I0 • S0 • S1 • S2 + I1 • S0 • S1 • S2 +
I2 • S0 • S1 • S2 + I3 • S0 • S1 • S2 +
I4 • S0 • S1 • S2 + I5 • S0 • S1 • S2 +
I6 • S0 • S1 • S2 + I7 • S0 • S1 • S2 +
When the Output Enable is HIGH, both outputs are in the high impedance
(high Z) state. This feature allows multiplexer expansion by tying the outputs
of up to 128 devices together. When the outputs of the 3-state devices are tied
together, all but one device must be in the high impedance state to avoid high
currents that would exceed the maximum ratings. The Output Enable signals
should be designed to ensure there is no overlap in the active LOW portion
of the enable voltages.
CONNECTION DIAGRAM
VCC I4 I5 I6 I7 S0 S1 S2
16 15 14 13 12 11 10 9
12345678
I3 I2 I1 I0 Z Z OE GND
MC54/74F251
8-INPUT MULTIPLEXER
WITH 3-STATE OUTPUTS
FAST™ SCHOTTKY TTL
16
1
J SUFFIX
CERAMIC
CASE 620-09
16
1
N SUFFIX
PLASTIC
CASE 648-08
16
1
D SUFFIX
SOIC
CASE 751B-03
ORDERING INFORMATION
MC54FXXXJ
MC74FXXXN
MC74FXXXD
Ceramic
Plastic
SOIC
LOGIC SYMBOL
9 10 11
S2 S1 S0
OE
7
I0
4
6
I1
3
I2
2
I3
1
I4
15
5
I5
14
I6
13
I7
12
VCC = PIN 16
GND = PIN 8
FAST AND LS TTL DATA
4-117
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