MOTOROLA SN74LS147D, SN74LS147DR2, SN74LS147N, SN74LS148D, SN74LS148DR2 Datasheet
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SN74LS147 SN74LS148
10-Line-to-4-Line and 8-Line-to-3-Line Priority Encoders
The SN74LS147 and the SN74LS148 are Priority Encoders. They provide priority decoding of the inputs to ensure that only the highest order data line is encoded. Both devices have data inputs and outputs which are active at the low logic level.
The LS147 encodes nine data lines to four-line (8-4-2-1) BCD. The implied decimal zero condition does not require an input condition because zero is encoded when all nine data lines are at a high logic level.
The LS148 encodes eight data lines to three-line (4-2-1) binary (octal). By providing cascading circuitry (Enable Input EI and Enable Output EO) octal expansion is allowed without needing external circuitry.
GUARANTEED OPERATING RANGES
Symbol |
Parameter |
Min |
Typ |
Max |
Unit |
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VCC |
Supply Voltage |
4.75 |
5.0 |
5.25 |
V |
TA |
Operating Ambient |
0 |
25 |
70 |
°C |
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Temperature Range |
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IOH |
Output Current ± High |
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± 0.4 |
mA |
IOL |
Output Current ± Low |
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8.0 |
mA |
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LOW
POWER
SCHOTTKY
16
1
PLASTIC
N SUFFIX
CASE 648
16
1
SOIC
D SUFFIX
CASE 751B
ORDERING INFORMATION
Device |
Package |
Shipping |
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SN74LS147N |
16 Pin DIP |
2000 Units/Box |
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SN74LS147D |
16 Pin |
2500/Tape & Reel |
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SN74LS148N |
16 Pin DIP |
2000 Units/Box |
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SN74LS148D |
16 Pin |
2500/Tape & Reel |
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Semiconductor Components Industries, LLC, 1999 |
1 |
Publication Order Number: |
December, 1999 ± Rev. 6 |
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SN74LS147/D |
SN74LS147 SN74LS148
SN74LS147
(TOP VIEW)
|
OUTPUT |
|
INPUTS |
|
OUTPUT |
||
VCC |
NC |
D |
3 |
2 |
1 |
9 |
A |
16 |
15 |
14 |
13 |
12 |
11 |
10 |
9 |
|
|
D |
3 |
2 |
1 |
9 |
|
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4 |
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|
A |
|
5 |
6 |
7 |
8 |
C |
B |
|
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
4 |
5 |
6 |
7 |
8 |
C |
B |
GND |
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|
INPUTS |
|
|
OUTPUTS |
||
SN74LS148
(TOP VIEW)
|
OUTPUTS |
|
INPUTS |
OUTPUT |
|||
VCC |
EO |
GS |
3 |
2 |
1 |
0 |
A0 |
16 |
15 |
14 |
13 |
12 |
11 |
10 |
9 |
|
EO |
GS |
3 |
2 |
1 |
0 |
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4 |
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A0 |
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5 |
6 |
7 |
EI |
A2 |
A1 |
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1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
4 |
5 |
6 |
7 |
E1 |
A2 |
A1 |
GND |
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INPUTS |
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OUTPUTS |
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2
SN74LS147 SN74LS148
SN74LS147
FUNCTION TABLE
INPUTS |
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OUTPUTS |
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1 2 3 4 5 6 7 8 9 |
D C B A |
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H H H H H H H H H |
H |
H H H |
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X X X X X X X X L |
L H H L |
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X X X X X X X L |
H |
L H H H |
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X X X X X X L |
H H |
H L L L |
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X X X X X L |
H H H |
H L L H |
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X X X X L H H H H |
H L H L |
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X X X L H H H H H |
H L H H |
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X X L H H H H H H |
H H L L |
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X L H H H H H H H |
H H L H |
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L H H H H H H H H |
H H H L |
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H = HIGH Logic Level, L = LOW Logic Level, X = Irrelevant
SN74LS148
FUNCTION TABLE
INPUTS |
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OUTPUTS |
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EI 0 1 2 3 4 5 |
6 |
7 |
A2 A1 A0 |
GS |
EO |
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H X X X X X X X X |
H H H |
H H |
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L H H H H H H H H |
H H H |
H |
L |
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L X X X X X X X L |
L L L |
L |
H |
||
L X X X X X X L |
H |
L L H |
L |
H |
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L X X X X X L |
H H |
L H L |
L |
H |
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L X X X X L H H H |
L H H |
L |
H |
||
L X X X L H H H H |
H L L |
L |
H |
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L X X L H H H H H |
H L H |
L |
H |
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L X L H H H H H H |
H H L |
L |
H |
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L L H H H H H H H |
H H H |
L |
H |
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FUNCTIONAL BLOCK DIAGRAMS |
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1 |
(11) |
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(10) |
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0 |
(15) |
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(12) |
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EO |
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2 |
(9) |
(11) |
(14) |
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1 |
GS |
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A |
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3 |
(13) |
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(12) |
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2 |
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(8) |
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(1) |
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(13) |
A0 |
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4 |
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3 |
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(2) |
(7) |
(1) |
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5 |
B |
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4 |
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(3) |
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(2) |
(7) |
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6 |
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A1 |
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5 |
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7 |
(4) |
(6) |
(3) |
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C |
6 |
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8 |
(5) |
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(4) |
(6) |
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7 |
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A2 |
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(10) |
(14) |
(5) |
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9 |
D |
EI |
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SN74LS147 |
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SN74LS148 |
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