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BCD-TO-SEVEN-SEGMENT DECODERS/DRIVERS. SN54LS249 Datasheet |
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BCD-TO-SEVEN-SEGMENT
DECODERS/DRIVERS
The SN54/74LS247 thru SN54/74LS249 are BCD-to-Seven-Segment
Decoder/Drivers.
The LS247 and LS248 are functionally and electrically identical to the LS47
and LS48 with the same pinout configuration. The LS249 is a 16-pin version
of the 14-pin LS49 and includes full functional capability for lamp test and
ripple blanking which was not available in the LS49.
The composition of all characters, except the 6 and 9 are identical between
the LS247, 248, 249 and the LS47, 48 and 49. The LS47 thru 49 compose
the and without tails, the LS247 thru 249 compose the and with
the tails. The LS247 has active-low outputs for direct drive of indicators. The
LS248 and 249 have active-high outputs for driving lamp buffers.
All types feature a lamp test input and have full ripple-blanking input/output
controls. On all types an automatic leading and/or trailing-edge zero-blanking
control (RBI and RBO) is incorporated and an overriding blanking input (BI)
is contained which may be used to control the lamp intensity by pulsing or to
inhibit the output’s lamp test may be performed at any time when the BI/RBO
node is at high level. Segment identification and resultant displays are shown
below. Display pattern for BCD input counts above 9 are unique symbols to
authenticate input conditions.
LS247
• Open-Collector Outputs Drive Indicators Directly
• Lamp-Test Provision
• Leading / Trailing Zero Suppression
LS248
• Internal Pull-Ups Eliminate Need for External Resistors
• Lamp-Test Provision
• Leading / Trailing Zero Suppression
LS249
• Open-Collector Outputs
• Lamp-Test Provision
• Leading / Trailing Zero Suppression
SN54/74LS247
SN54/74LS248
SN54/74LS249
BCD-TO-SEVEN-SEGMENT
DECODERS/ DRIVERS
LOW POWER SCHOTTKY
16
1
16
1
16
1
J SUFFIX
CERAMIC
CASE 620-09
N SUFFIX
PLASTIC
CASE 648-08
D SUFFIX
SOIC
CASE 751B-03
ORDERING INFORMATION
SN54LSXXXJ Ceramic
SN74LSXXXN Plastic
SN74LSXXXDW SOIC
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
NUMERICAL DESIGNATIONS AND RESULTANT DISPLAYS
a
fgb
ec
d
SEGMENT
IDENTIFICATION
FAST AND LS TTL DATA
5-402
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SN54/74LS247 • SN54/74LS248 • SN54/74LS249
SN54 / 74LS247
(TOP VIEW)
OUTPUTS
VCC
f
g
abc
de
16 15 14 13 12 11 10 9
f g a bc d e
BI/
B C LT RBORBI D A
12
BC
INPUTS
345
LAMP
TEST
RB
OUT
PUT
RB
IN
PUT
67
DA
INPUTS
8
GND
SN54 / 74LS248
SN54 / 74LS259
(TOP VIEW)
OUTPUTS
VCC
f
g
abc
de
16 15 14 13 12 11 10 9
f g a bc d e
BI/
B C LT RBORBI D A
12
BC
INPUTS
345
LAMP
TEST
RB
OUT
PUT
RB
IN
PUT
67
DA
INPUTS
8
GND
ALL CIRCUIT TYPES FEATURE LAMP INTENSITY MODULATION CAPABILITY
TYPE
ACTIVE
LEVEL
DRIVER OUTPUTS
OUTPUT
SINK
CONFIGURATION CURRENT
MAX
VOLTAGE
TYPICAL
POWER
DISSIPATION
SN54LS247
SN54LS248
SN54LS249
low
high
high
open-collector
2.0 kΩ pull-up
open-collector
12 mA
2.0 mA
4.0 mA
15 V
5.5 V
5.5 V
35 mW
125 mW
40 mW
SN74LS247
SN74LS248
SN74LS249
low
high
high
open-collector
2.0 kΩ pull-up
open-collector
24 mA
6.0 mA
8.0 mA
15 V
5.5 V
5.5 V
35 mW
125 mW
40 mW
INPUT (7)
A
INPUT (1)
B
INPUT (2)
C
INPUT (6)
D
BI/RBO
BLANKING
(4)
INPUT OR
RIPPLEĆBLANKING
OUTPUT
(3)
LAMP TEST
INPUT
RBI
(5)
RIPPLEĆBLANKING
INPUT
LS247
LOGIC DIAGRAM
(13)
OUTPUT
a
(12)
OUTPUT
b
(11)
OUTPUT
c
(10)
OUTPUT
d
(9)
OUTPUT
e
(15)
OUTPUT
f
(14)
OUTPUT
g
INPUT (7)
A
INPUT (1)
B
INPUT (2)
C
INPUT (6)
D
BLANKING
INPUT OR
(4)
RIPPLEĆBLANKING
OUTPUT
(3)
LAMP TEST
INPUT
(5)
RIPPLEĆBLANKING
INPUT
FAST AND LS TTL DATA
5-403
LS248, LS249
(13)
OUTPUT
a
(12)
OUTPUT
b
(11)
OUTPUT
c
(10)
OUTPUT
d
(9)
OUTPUT
e
(15)
OUTPUT
f
(14)
OUTPUT
g
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SN54/74LS247 • SN54/74LS248 • SN54/74LS249
LS247
FUNCTION TABLE
DECIMAL
OR
INPUTS
BI/RBO
OUTPUTS
NOTE
FUNCTION LT RBI D C B A
abcde f g
0
HHL L L L
H ON ON ON ON ON ON OFF
1
HXL L LH
H OFF ON ON OFF OFF OFF OFF
2
HXL LHL
H ON ON OFF ON ON OFF ON
3 H X L L H H H ON ON ON ON OFF OFF ON
4
HXLHL L
H OFF ON ON OFF OFF ON ON
5 H X L H L H H ON OFF ON ON OFF ON ON
6
HX LHHL
H ON OFF ON ON ON ON ON
7
HX LHHH
H
ON ON ON OFF OFF OFF OFF
1
8
HXHL L L
H ON ON ON ON ON ON ON
9 H X H L L H H ON ON ON ON OFF ON ON
10 H X H L H L H OFF OFF OFF ON ON OFF ON
11
HXH L HH
H OFF OFF ON ON OFF OFF ON
12 H X H H L L H OFF ON OFF OFF OFF ON ON
13 H X H H L H H ON OFF OFF ON OFF ON ON
14 H X H H H L H OFF OFF OFF ON ON ON ON
15 H X H H H H H OFF OFF OFF OFF OFF OFF OFF
BI X X X X X X
RBI H L L L L L
LT L X X X X X
L OFF OFF OFF OFF OFF OFF OFF 2
L OFF OFF OFF OFF OFF OFF OFF 3
H ON ON ON ON ON ON ON 4
LS248, LS249
FUNCTION TABLE
DECIMAL
OR
INPUTS
BI/RBO
OUTPUTS
FUNCTION LT RBI D C B A
abcde f g
NOTE
0 HHL L L L H H H H H H H L 1
1
HXL L LH
H
LHH L L L L
1
2 HXL LHL H H H L H H L H
3 HX L LHH H H H H H L L H
4
HXLHL L
H
LHH L LHH
5 HXLHLH H H L H H L H H
6 HX LHHL H H L H H H H H
7 HX LHHH H H H H L L L L 1
8 HXHL L L H H H H H H H H
9 HXHL LH H H H H H L H H
10 H X H L H L H L L L H H L H
11
HXH L HH
H
L LHHL LH
12 H X H H L L H L H L L L H H
13 H X H H L H H H L L H L H H
14 H X H H H L H L L L H H H H
15
HXHHHH
H
LLL LLLL
BI
XXXXXX
L
LLL LLLL
RBI H L L L L L L L L L L L L L
LT L X X X X X H H H H H H H H
2
3
4
H = HIGH Level, L = LOW Level, X = Irrelevant
NOTES: 1. The blanking input (BI) must be open or held at a high logic level when output functions 0 through 15 are desired. The ripple-blanking input (RBI) must
NOTES: 1. be open or high if blanking of a decimal zero is not desired.
2. When a low logic level is applied directly to the blanking input (BI), all segment outputs are off regardless of the level of any other input.
3. When ripple-blanking input (RBI) and inputs A, B, C, and D are at a low level with the lamp test input high, all segment outputs go off and the
NOTES: 1. ripple-blanking output (RBO) goes to a low level (response condition).
4. When the blanking input/ripple blanking output (BI/RBO) is open or held high and a low is applied to the lamp-test input, all segment outputs are on.
BI/RBO is wire-AND logic serving as blanking input (BI) and/or ripple-blanking output (RBO).
FAST AND LS TTL DATA
5-404
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