74LS48 Datasheet, PDF (3/6 Pages) National Semiconductor (TI) – BCD to 7-Segment Decoder

Numerical Designations Resultant Displays
TL F 10172 – 4
Truth Table
Decimal
Or
Function
Inputs
Outputs
LT RBI A₃ A₂ A₁ A₀ BI RBO a b c d e f g
0 (Note 1) H
H
L
L
L
L
1 (Note 1) H
X
L
L
L
H
2
H
X
L
L
H
L
3
H
X
L
L
H
H
H
HHHHHH L
H
LHHL L L L
H
HH L HH L H
H
HHHHL LH
4
H
X
L
H
L
L
H
LHHL LHH
5
H
X
L
H
L
H
H
H L HH L HH
6
H
X
L
H
H
L
H
L LHHHHH
7
H
X
L
H
H
H
H
HHHL L L L
8
H
X
H
L
L
L
H
HHHHHHH
9
H
X
H
L
L
H
H
HHHL LHH
10
H
X
H
L
H
L
H
L L LHHLH
11
H
X
H
L
H
H
H
L LHHL LH
12
H
X
H
H
L
L
H
LHL L LHH
13
H
X
H
H
L
H
H
HL LHLHH
14
H
X
H
H
H
L
15
H
X
H
H
H
H
BI (Note 2) X
X
X
X
X
X
RBI (Note 3) H
L
L
L
L
L
LT (Note 4) L
X
X
X
X
X
H
L L LHHHH
H
LLLLLLL
L
LLLLLLL
L
LLLLLLL
H
HHHHHHH
Note 1 BI RBO is wired-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 e input
may be HIGH or LOW
Note 2 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
Note 3 When ripple-blanking input (RBI) and inputs A₀ A₁ A₂ and A₃ are at LOW level with the lamp test input at HIGH level all segment outputs go to a LOW
level and the ripple-blanking output (RBO) goes to a LOW level (response condition)
Note 4 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 HIGH level
Logic Symbol
V_CC e Pin 16
GND e Pin 8
TL F 10172 – 2
3