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TYPES~SN5446A, '47A;""'48. '4975^54146, 'L47, SN54LS47, 'LS48, 'LS49;
SN7446A, '47A. '48, SN74L46, 'L47, SN74LS47, 'LS48, 'LS49
BCD-TO-SEVEN-SEGMENT DECODERS/DR1VERS
descriptíon
The '46A, 'L.46, '47A, 'L47, and 'LS47 feature active-Iow outputs designed for driving comrnon-anode VLEDs or
incandescent Indicators directiy. and the '48, '49, 'LS48, 'LS49 feature actíve-high outputs for driving lamp buffers or
cammon-cathode VLEDs. AII of the circuits except '49 and 'LS49 have full ripple-blanking input/output controls and a
lamp IESE input. The '49 and 'LS49 circuits incorpórate a direct blanking input,. Segment identification and resultant
displays are shown below. Dísplay patterns for SCD input counts above 9 are unique symbols to authenticate ¡nput
conditíons.
The '46A, '47A, '48, 'L46, 'L47, 'LS47, and 'LS48 circuits incorpórate automatic leading ánd/or trailing-edge
zero-blanking control {RBI and RBO). Lamp test (LT) of tríese types may be performed at any time when the BI/RBO
node ¡s at a high leveí. AII types (including the '49 and 'LS49) contaín an overridíng blanking input (Bl) whichcan be
used to control the lamp intensity by pulsing or to inhibít the outputs. Inputs and outputs are entírely compatible for
use with TTL or DTL íogic outputs.
The SN54246/SN74246 through '249 and the SN54LS247/SN74LS24? through 'LS249 campóse che B and
the 9 w¡th taíls and have been designad to offer the designer a cholee between cwo índícator fonts. The
SN54249/SN74249 and SM54LS249/SN74LS249 are IB-pin versions of the 14-pin SN5449 and 'LS49. Inctuded ín the
'249 circuít and 'LS249 circuits are the full functional capabilíty for lamp test and ripple blanking, which ¡s
not available in the '49 or 'LS49 círcuit.
SEGMENT
IDENTIFICATION
DECIMAL
OR
FUNCTION
a
1
2
3
4
5
6
7
B
9
10
11
12
13
14
15
Bl
RB!
Lf
LT
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
X
H
L
R8I
H
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
L
X
1 '1
1 1
1NPUTS
o i i~i
o a i_ ZI L_J i~ i_
1
1
1 P _l
1
1
1
1
1
2 3 4 5 6 7 8 9 10 11 12 13
NUMERICAL QESIGNAT1ONS ANO RESULTANT DISPLAYS
"¿GA, '47A. 'L4S, 'L¿7, 'LS-17 FUNCTION TABLE
D C B A
L L L L
L L L H
L L H L
L L H H
L H L U
L H L H
L H H L
L H H H
H L L L
H L L H
H L H L
H L H H
H H L L
H H L H
H H H L
H H H H
X X X X
L L L L
X X X X
OUTPUTS
BI/RBO'"
i h c d a f
H ON ON ON QN ON ON
H OFF ON ON OFF OFF OFF
H ON ON OFF ON ON OFF
H ON ON ON ON OFF OFF
H OFF ON ON OFF OFF ON
H ON OFF ON ON OFF ON
H OFF OFF ON ON ON ON
H ON ON ON QFF OFF OFF
H QN ON QN ON ON ON
H ON ON QN OFF OFF ON
H OFF OFF OFF ON ON OFF
H OFF OFF ON ON OFF OFF
H OFF ON OFF OFF OFF ON
H ON OFF OFF ON OFF ON
H OFF OFF OFF ON ON ON
H OFF OFF OFF OFF OFF OFF
L OFF OFF QFF OFF OFF OFF
L OFF OFF OFF OFF OFF OFF
H ON ON ON ON ON ON
H - nIqn
l.v.1. U - lo- I.V.É. X - irr» «.ni
NOTES; 1. Tíi» bUnkioq inoui IBI) mun b« ao*r\r h«td at a tiign logic l«v«l wtiin oufpur tuncnoni O inrougn |S ir* d«l(« tt t low Iwvl with th« l—np tm ínout h«jh, sil wgir
90 oH and tn« rip0l«-{>4*nkl(>9 OUCDUT (RBOI go*i to . lo» |wwl (cnooni* condiiion).
«qmnnt OutoUQ itrm an.
f BI/R8Q U wiro-ANO loqíc «rving ti blankínq InQut (Bl) *nd/«r rioal«-bl'n«Iiv) OutputlRBO).
TEXAS INSTRUMENTS
I;N COR POR ATEO
1
OFF
OFF
ON
ON
ON
ON
ON
OFF
ON
ON
ON
ON
ON
ON
ON
OFF
OFF
OFF
ON
NOTE
1
2
3
4