SN54/74LS47
BCD TO 7-SEGMENT
DECODER/DRIVER
The SN54 / 74LS47 are Low Power Schottky BCD to 7-Segment Decod-
er / Drivers consisting of NAND gates, input buffers and seven AND-OR-IN-
VERT 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 SN54 / 74LS47 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 SN54 / 74LS47 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.
BCD TO 7-SEGMENT
DECODER/ DRIVER
LOW POWER SCHOTTKY
J SUFFIX
CERAMIC
CASE 620-09
16
1
16
1
N SUFFIX
PLASTIC
CASE 648-08
•
•
•
•
•
Lamp Intensity Modulation Capability (BI/RBO)
Open Collector Outputs
Lamp Test Provision
Leading / Trailing Zero Suppression
Input Clamp Diodes Limit High-Speed Termination Effects
CONNECTION DIAGRAM DIP
(TOP VIEW)
VCC
16
f
15
g
14
a
13
b
12
c
11
d
10
e
9
16
1
D SUFFIX
SOIC
CASE 751B-03
ORDERING INFORMATION
SN54LSXXJ
SN74LSXXN
SN74LSXXD
Ceramic
Plastic
SOIC
LOGIC SYMBOL
7 1 2 6 3 5
1
B
PIN NAMES
A, B, C, D
RBI
LT
BI / RBO
a, to g
BCD Inputs
Ripple-Blanking Input
Lamp-Test Input
Blanking Input or
Ripple-Blanking Output
Outputs
2
C
3
4
5
6
D
7
A
HIGH
0.5 U.L.
0.5 U.L.
0.5 U.L.
0.5 U.L.
1.2 U.L.
Open-Collector
8
GND
LOW
0.25 U.L.
0.25 U.L.
0.25 U.L.
0.75 U.L.
2.0 U.L.
15 (7.5) U.L.
A B C D LT RBI
BI/
f g RBO
LT BI / RBO RBI
LOADING
(Note a)
a
b c d
e
13 12 11 10 9 15 14 4
VCC = PIN 16
GND = PIN 8
NOTES:
a) 1 Unit Load (U.L.) = 40
µA
HIGH, 1.6 mA LOW.
b) Output current measured at VOUT = 0.5 V
The Output LOW drive factor is 7.5 U.L. for Military (54) and 15 U.L. for Commercial (74) Temperature Ranges.
FAST AND LS TTL DATA
5-56
SN54/74LS47
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.
FAST AND LS TTL DATA
5-57
SN54/74LS47
GUARANTEED OPERATING RANGES
Symbol
VCC
TA
IOH
IOL
VO (off)
IO (on)
Supply Voltage
Operating Ambient Temperature Range
Output Current — High
Output Current — Low
BI / RBO
BI / RBO
BI / RBO
Parameter
54
74
54
74
54, 74
54
74
54, 74
54
74
Min
4.5
4.75
– 55
0
Typ
5.0
5.0
25
25
Max
5.5
5.25
125
70
– 50
1.6
3.2
15
12
24
Unit
V
°C
µA
mA
V
mA
Off-State Output Voltage a to g
On-State Output Current a to g
On-State Output Current
a to g
DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE
(unless otherwise specified)
Limits
Symbol
VIH
VIL
VIK
VOH
VOL
IO (off)
VO (on)
IIH
IIL
IOS BI / RBO
ICC
Parameter
Input HIGH Voltage
Input LOW Voltage
Input Clamp Diode Voltage
Output HIGH Voltage, BI / RBO
Output LOW Voltage
BI / RBO
Off-State Output Current
a thru g
On-State Output Voltage
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
54, 74
74
0.25
0.35
54, 74
74
2.4
54
74
– 0.65
4.2
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
0.7
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
VCC = MIN, IIN = – 18 mA
VCC = MIN, IOH = – 50
µA,
VIN = VIN or VIL per Truth Table
IOL = 1.6 mA
IOL = 3.2 mA
VCC = MIN, VIN = VIN or
VIL per Truth Table
VCC = MAX, VIN = VIN or VIL per Truth
Table, VO (off) = 15 V
IO (on) = 12 mA
IO (on) = 24 mA
VCC = MAX, VIN = VIH
or VIL per Truth Table
VCC = MAX, VIN = 2.7 V
VCC = MAX, VIN = 7.0 V
VCC = MAX, VIN = 0.4 V
VCC = MAX, VOUT = 0 V
VCC = MAX
Note 1: Not more than one output should be shorted at a time, nor for more than 1 second.
AC CHARACTERISTICS
(TA = 25°C)
Limits
Symbol
tPHL
tPLH
tPHL
tPLH
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
VCC = 5.0 V
CL = 15 pF
AC WAVEFORMS
1.3 V
tPHL
VOUT
1.3 V
1.3 V
tPLH
1.3 V
VOUT
VIN
VIN
1.3 V
tPHL
1.3 V
1.3 V
tPLH
1.3 V
Figure 1
Figure 2
FAST AND LS TTL DATA
5-58
51单片机
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