HD74LS48
Function Table
Decimal or
Inputs
BI /
Outputs
Function LT RBI D C B A RBO a
b
c
d
e
f
Note
g
0
H H LLLL
H
HHHHHH L
1
H X LLLH
H
LHHL L L L
2
H X LLHL
H
HHLHHL H
3
H X L LHH
H
HHHHL L H
4
H X LHLL
H
LHHL LHH
5
H X LHLH
H
H L HH L HH
6
H X LHHL
H
L LHHHHH
7
H X LHHH
H
HHHL L L L
1
8
H X HLLL
H
HHHHHHH
9
H X HLLH
H
HHHL LHH
10
H X HLHL
H
L L LHHLH
11
H X HLHH
H
L LHHL L H
12
H X HHL L
H
LHL L LHH
13
H X HHLH
H
HL LHLHH
14
H X HHHL
H
L L LHHHH
15
H X HHHH
H
LLLLLLL
BI
X X XXXX
L
LLLL
LLL
2
RBI
H L LLLL
L
LLLL
LLL
3
LT
L X XXXX
H
HHHHHHH
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.
2. When a low logic level is applied directly to the blanking input (BI), all segment outputs are low 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 low and the ripple-blanking output (RBO) goes to a low level (response condition).
4. When a 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 high.
a
f gb
ec
d 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Rev.3.00, Jul.22.2005, page 2 of 6
