Semiconductor Components Industries, LLC, 1999
December, 1999 – Rev. 6 1Publication Order Number:
SN74LS147/D
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
VCC Supply Voltage 4.75 5.0 5.25 V
TAOperating Ambient
Temperature Range 0 25 70 °C
IOH Output Current – High –0.4 mA
IOL Output Current – Low 8.0 mA
LOW
POWER
SCHOTTKY
Device Package Shipping
ORDERING INFORMATION
SN74LS147N 16 Pin DIP 2000 Units/Box
SN74LS147D 16 Pin
SOIC
D SUFFIX
CASE 751B
http://onsemi.com
2500/Tape & Reel
PLASTIC
N SUFFIX
CASE 648
16
1
16
1
SN74LS148N 16 Pin DIP
SN74LS148D 16 Pin
2000 Units/Box
2500/Tape & Reel
SN74LS147 SN74LS148
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2
SN74LS147
(TOP VIEW)
SN74LS148
(TOP VIEW)
4 5 6 7 8 C B GND
D3219AVCC NC 14 13 12 11 10 9
1234567
16 15
8
D321 9
A4
5678CB
OUTPUT INPUTS OUTPUT
INPUTS OUTPUTS
4 5 6 7 E1 A2 A1 GND
VCC EO GS 3 2 1 0 A0
14 13 12 11 10 9
1234567
16 15
8
EO GS 3 2 1 0
A04
56 7EIA2A1
OUTPUTS INPUTS OUTPUT
INPUTS OUTPUTS
SN74LS147 SN74LS148
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3
SN74LS147
FUNCTION TABLE
INPUTS OUTPUTS
1 2 3 4 5 6 7 8 9 D C B A
H H H H H H H H H H H H H
XXXXXXXXLLHHL
XXXXXXXLHLHHH
XXXXXXLHHHLLL
XXXXXLHHHHLLH
XXXXLHHHHHLHL
XXXLHHHHHHLHH
XXLHHHHHHHHLL
XLHHHHHHHHHLH
L H H H H H H H H H H H L
SN74LS148
FUNCTION TABLE
INPUTS OUTPUTS
EI 0 1 2 3 4 5 6 7 A2 A1 A0 GS EO
H X X X X X X X X H H H H H
LHHHHHHHH H HHH L
LXXXXXXXL L LLL H
LXXXXXXLH L LH L H
LXXXXXLHH L HL L H
LXXXXLHHH L HH L H
LXXXLHHHH H LLL H
LXXLHHHHH H LH L H
LXLHHHHHH H HL L H
L L H H H H H H H H H H L H
H = HIGH Logic Level, L = LOW Logic Level, X = Irrelevant
FUNCTIONAL BLOCK DIAGRAMS
SN74LS147 SN74LS148
1
2
3
4
5
6
7
8
9
(11)
(12)
(13)
(1)
(2)
(3)
(4)
(5)
(10)
(9)
(7)
(6)
(14)
A
B
C
D
0
1
2
3
4
5
6
7
EI
(10)
(11)
(12)
(13)
(1)
(2)
(3)
(4)
(5)
(15) EO
(14) GS
(8) A0
(7) A1
(6) A2
SN74LS147 SN74LS148
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4
DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE (unless otherwise specified)
Limits
Symbol Parameter Min Typ Max Unit Test Conditions
VIH Input HIGH Voltage 2.0 VGuaranteed Input HIGH Voltage for
All Inputs
VIL Input LOW Voltage 0.8 VGuaranteed Input LOW Voltage for
All Inputs
VIK Input Clamp Diode Voltage –0.65 –1.5 V VCC = MIN, IIN = –18 mA
VOH Output HIGH Voltage 2.7 3.5 V VCC = MIN, IOH = MAX, VIN = VIH
or VIL per T ruth Table
VO
Out
p
ut LOW Voltage
0.25 0.4 V IOL = 4.0 mA VCC = VCC MIN,
VIN =V
IL or VIH
V
OL
O
u
tp
u
t
LOW
Voltage
0.35 0.5 V IOL = 8.0 mA
V
IN =
V
IL
or
V
IH
per T ruth Table
IIH
Input HIGH Current
All Others
Inputs 1–7 (LS148) 20
40 µA VCC = MAX, VIN = 2.7 V
IH
All Others
Inputs 1–7 (LS148) 0.1
0.2 mA VCC = MAX, VIN = 7.0 V
IIL
Input LOW Current
All Others
Inputs 1–7 (LS148) –0.4
–0.8 mA VCC = MAX, VIN = 0.4 V
IOS Short Circuit Current (Note 1) –20 –100 mA VCC = MAX
ICCH Power Supply Current Output HIGH 17 mA VCC = MAX, All Inputs = 4.5 V
ICCL Output LOW 20 mA VCC = MAX, Inputs 7 & E1 = GND
All Other Inputs = 4.5 V
Note 1: Not more than one output should be shorted at a time, nor for more than 1 second.
SN74LS147 SN74LS148
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5
AC CHARACTERISTICS (VCC = 5.0 V, TA = 25 °C)
SN74LS147
From To Limits
Symbol
From
(Input)
To
(Output) Waveform Min Typ Max Unit Test Conditions
tPLH
Any
Any
In-phase 12 18
ns
tPHL
An
y
An
youtput 12 18
ns
CL = 15 pF,
tPLH
Any
Any
Out-of-phase 21 33
ns
L
RL = 2.0 kΩ
tPHL
An
y
An
youtput 15 23
ns
SN74LS148
From To Limits
Symbol
From
(Input)
To
(Output) Waveform Min Typ Max Unit Test Conditions
tPLH
1 thru 7
A0 A1 or A2
In-phase 14 18
ns
tPHL
1
thr
u
7
A0
,
A1
,
or
A2
output 15 25
ns
tPLH
1 thru 7
A0 A1 or A2
Out-of-phase 20 36
ns
tPHL
1
thr
u
7
A0
,
A1
,
or
A2
output 16 29
ns
tPLH
0 thru 7
EO
Out-of-phase 7.0 18
ns
tPHL
0
thr
u
7
EO
output 25 40
ns
C 15 F
tPLH
0 thru 7
GS
In-phase 35 55
ns
CL = 15 pF,
R
L
= 2.0 kΩ
tPHL
0
thr
u
7
GS
output 9.0 21
ns
RL
2.0
kΩ
tPLH
EI
A0 A1 or A2
In-phase 16 25
ns
tPHL
EI
A0
,
A1
,
or
A2
output 12 25
ns
tPLH
EI
GS
In-phase 12 17
ns
tPHL
EI
GS
output 14 36
ns
tPLH
In-
p
hase
12 21
tPHL EI EO
In
-
hase
output 28
30 40
45 ns (LS148)
SN74LS147 SN74LS148
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6
PACKAGE DIMENSIONS
N SUFFIX
PLASTIC PACKAGE
CASE 648–08
ISSUE R
NOTES:
1. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
2. CONTROLLING DIMENSION: INCH.
3. DIMENSION L TO CENTER OF LEADS WHEN
FORMED PARALLEL.
4. DIMENSION B DOES NOT INCLUDE MOLD FLASH.
5. ROUNDED CORNERS OPTIONAL.
–A–
B
FC
S
HGD
J
L
M
16 PL
SEATING
18
916
K
PLANE
–T–
M
A
M
0.25 (0.010) T
DIM MIN MAX MIN MAX
MILLIMETERSINCHES
A0.740 0.770 18.80 19.55
B0.250 0.270 6.35 6.85
C0.145 0.175 3.69 4.44
D0.015 0.021 0.39 0.53
F0.040 0.70 1.02 1.77
G0.100 BSC 2.54 BSC
H0.050 BSC 1.27 BSC
J0.008 0.015 0.21 0.38
K0.110 0.130 2.80 3.30
L0.295 0.305 7.50 7.74
M0 10 0 10
S0.020 0.040 0.51 1.01
____
SN74LS147 SN74LS148
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7
PACKAGE DIMENSIONS
D SUFFIX
PLASTIC SOIC PACKAGE
CASE 751B–05
ISSUE J
NOTES:
1. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
2. CONTROLLING DIMENSION: MILLIMETER.
3. DIMENSIONS A AND B DO NOT INCLUDE
MOLD PROTRUSION.
4. MAXIMUM MOLD PROTRUSION 0.15 (0.006)
PER SIDE.
5. DIMENSION D DOES NOT INCLUDE DAMBAR
PROTRUSION. ALLOWABLE DAMBAR
PROTRUSION SHALL BE 0.127 (0.005) TOTAL
IN EXCESS OF THE D DIMENSION AT
MAXIMUM MATERIAL CONDITION.
18
16 9
SEATING
PLANE
F
J
M
RX 45
_
G
8 PLP
–B–
–A–
M
0.25 (0.010) B S
–T–
D
K
C
16 PL
S
B
M
0.25 (0.010) A S
T
DIM MIN MAX MIN MAX
INCHESMILLIMETERS
A9.80 10.00 0.386 0.393
B3.80 4.00 0.150 0.157
C1.35 1.75 0.054 0.068
D0.35 0.49 0.014 0.019
F0.40 1.25 0.016 0.049
G1.27 BSC 0.050 BSC
J0.19 0.25 0.008 0.009
K0.10 0.25 0.004 0.009
M0 7 0 7
P5.80 6.20 0.229 0.244
R0.25 0.50 0.010 0.019
____
SN74LS147 SN74LS148
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8
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