SN74LS47
BCD to 7-Segment
Decoder/Driver
The SN74LS47 are Low Power Schottky BCD to 7-Segment
Decoder/ Drivers consisting of NAND gates, input buffers and seven
AND-OR-INVERT gates. They offer active LOW, high sink current
outputs for driving indicators directly. Seven NAND gates and one
driver are connected in pairs to make BCD data and its complement
available to the seven decoding AND-OR-INVERT gates. The
remaining NAND gate and three input buffers provide lamp test,
blanking input / ripple-blanking output and ripple-blanking input.
The circuits accept 4-bit binary-coded-decimal (BCD) and,
depending on the state of the auxiliary inputs, decodes this data to
drive a 7-segment display indicator. The relative positive-logic output
levels, as well as conditions required at the auxiliary inputs, are shown
in the truth tables. Output configurations of the SN74LS47 are
designed to withstand the relatively high voltages required for
7-segment indicators.
These outputs will withstand 15 V with a maximum reverse current
of 250
µA.
Indicator segments requiring up to 24 mA of current may
be driven directly from the SN74LS47 high performance output
transistors. Display patterns for BCD input counts above nine are
unique symbols to authenticate input conditions.
The SN74LS47 incorporates automatic leading and / or trailing-edge
zero-blanking control (RBI and RBO). Lamp test (LT) may be
performed at any time which the BI / RBO node is a HIGH level. This
device also contains an overriding blanking input (BI) which can be
used to control the lamp intensity by varying the frequency and duty
cycle of the BI input signal or to inhibit the outputs.
•
Lamp Intensity Modulation Capability (BI/RBO)
•
Open Collector Outputs
•
Lamp Test Provision
•
Leading/ Trailing Zero Suppression
•
Input Clamp Diodes Limit High-Speed Termination Effects
GUARANTEED OPERATING RANGES
Symbol
V
CC
T
A
I
OH
I
OL
Parameter
Supply Voltage
Operating Ambient
Temperature Range
Output Current – High
BI/RBO
Output Current – Low
BI/RBO
BI/RBO
Off–State Output Voltage
a to g
On–State Output Current
a to g
Min
4.75
0
Typ
5.0
25
Max
5.25
70
– 50
3.2
Unit
V
°C
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LOW
POWER
SCHOTTKY
16
1
PLASTIC
N SUFFIX
CASE 648
16
1
SOIC
D SUFFIX
CASE 751B
ORDERING INFORMATION
Device
SN74LS47N
SN74LS47D
Package
16 Pin DIP
16 Pin
Shipping
2000 Units/Box
2500/Tape & Reel
m
A
mA
V
O(off)
I
O(on)
15
24
V
mA
©
Semiconductor Components Industries, LLC, 1999
1
December, 1999 – Rev. 6
Publication Order Number:
SN74LS47/D
SN74LS47
LOGIC DIAGRAM
a
A
b
B
INPUT
C
D
d
BLANKING INPUT OR
RIPPLE-BLANKING
OUTPUT
d
c
c
OUTPUT
b
a
e
e
f
LAMP-TEST INPUT
RIPPLE-BLANKING
INPUT
f
g
g
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15
NUMERICAL DESIGNATIONS — RESULTANT DISPLAYS
TRUTH TABLE
INPUTS
DECIMAL
OR
FUNCTION
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
BI
RBI
LT
OUTPUTS
LT
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
X
H
L
RBI
H
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
L
X
D
L
L
L
L
L
L
L
L
H
H
H
H
H
H
H
H
X
L
X
C
L
L
L
L
H
H
H
H
L
L
L
L
H
H
H
H
X
L
X
B
L
L
H
H
L
L
H
H
L
L
H
H
L
L
H
H
X
L
X
A
L
H
L
H
L
H
L
H
L
H
L
H
L
H
L
H
X
L
X
BI/RBO
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
L
L
H
a
L
H
L
L
H
L
H
L
L
L
H
H
H
L
H
H
H
H
L
b
L
L
L
L
L
H
H
L
L
L
H
H
L
H
H
H
H
H
L
c
L
L
H
L
L
L
L
L
L
L
H
L
H
H
H
H
H
H
L
d
L
H
L
L
H
L
L
H
L
H
L
L
H
L
L
H
H
H
L
e
L
H
L
H
H
H
L
H
L
H
L
H
H
H
L
H
H
H
L
f
L
H
H
H
L
L
L
H
L
L
H
H
L
L
L
H
H
H
L
g
H
H
L
L
L
L
L
H
L
L
L
L
L
L
L
H
H
H
L
NOTE
A
A
B
C
D
H = HIGH Voltage Level
L = LOW Voltage Level
X = Immaterial
NOTES:
(A) BI/RBO is wire-AND logic serving as blanking Input (BI) and/or ripple-blanking output (RBO). The blanking out (BI) must be open or
held at a HIGH level when output functions 0 through 15 are desired, and ripple-blanking input (RBI) must be open or at a HIGH level
if blanking of a decimal 0 is not desired. X = input may be HIGH or LOW.
(B) When a LOW level is applied to the blanking input (forced condition) all segment outputs go to a LOW level regardless of the state
of any other input condition.
(C) When ripple-blanking input (RBI) and inputs A, B, C, and D are at LOW level, with the lamp test input at HIGH level, all segment outputs
go to a HIGH level and the ripple-blanking output (RBO) goes to a LOW level (response condition).
(D) When the blanking input/ripple-blanking output (BI/RBO) is open or held at a HIGH level, and a LOW level is applied to lamp test input,
all segment outputs go to a LOW level.
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3
SN74LS47
DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE
(unless otherwise specified)
Limits
Symbol
V
IH
V
IL
V
IK
V
O
OH
V
O
OL
I
O (off)
V
O (on)
( )
I
IH
I
IL
I
OS
BI / RBO
I
CC
Parameter
Input HIGH Voltage
Input LOW Voltage
Input Clamp Diode Voltage
Output HIGH Voltage BI / RBO
Voltage,
Output LOW Voltage
g
BI / RBO
Off-State Output Current
a thru g
On-State Output Voltage
g
a thru g
Input HIGH Current
Input LOW Current BI / RBO
Any Input except BI / RBO
Output Short Circuit Current (Note 1)
Power Supply Current
– 0.3
7.0
0.25
0.35
2.4
24
– 0.65
4.2
42
0.25
0.35
0.4
0.5
250
0.4
0.5
20
0.1
– 1.2
– 0.4
–2.0
13
Min
2.0
0.8
– 1.5
Typ
Max
Unit
V
V
V
V
V
V
µA
V
V
µA
mA
mA
mA
mA
Test Conditions
Guaranteed Input HIGH Theshold Voltage
for All Inputs
Guaranteed Input LOW Threshold Voltage
for All Inputs
V
CC
= MIN, I
IN
= – 18 mA
V
CC
= MIN, I
OH
= – 50
µ
µA,
V
IN
= V
IN
or V
IL
per Truth Table
I
OL
= 1.6 mA
I
OL
= 3.2 mA
V
CC
= MIN, V
IN
= V
IN
or V
IL
per Truth Table
V
CC
= MAX, V
IN
= V
IN
or V
IL
per Truth
Table, V
O (off)
= 15 V
I
O (on)
= 12 mA
I
O (on)
= 24 mA
V
CC
= MAX, V
IN
= V
IH
or V
IL
per Truth Table
V
CC
= MAX, V
IN
= 2.7 V
V
CC
= MAX, V
IN
= 7.0 V
V
CC
= MAX, V
IN
= 0.4 V
V
CC
= MAX, V
OUT
= 0 V
V
CC
= MAX
Note 1: Not more than one output should be shorted at a time, nor for more than 1 second.
AC CHARACTERISTICS
(T
A
= 25°C)
Limits
Symbol
t
PHL
t
PLH
t
PHL
t
PLH
Parameter
Propagation Delay, Address
Input to Segment Output
Propagation Delay, RBI Input
To Segment Output
Min
Typ
Max
100
100
100
100
Unit
ns
ns
ns
ns
Test Conditions
V
CC
= 5.0 V
C
L
= 15 pF
AC WAVEFORMS
V
IN
1.3 V
t
PHL
1.3 V
t
PLH
1.3 V
1.3 V
V
IN
1.3 V
t
PHL
1.3 V
t
PLH
1.3 V
V
OUT
V
OUT
1.3 V
Figure 1.
Figure 2.
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