HD74LS48

Rev.3.00, Jul.22.2005, page 2 of 6

Function Table

Inputs

Outputs

Decimal or

Function

LT

RBI

D

C

B

A

BI /

RBO

a

b

c

d

e

f

g

Note

0

H

H

L

L

L

L

H

H

H

H

H

H

H

L

1

H

X

L

L

L

H

H

L

H

H

L

L

L

L

2

H

X

L

L

H

L

H

H

H

L

H

H

L

H

3

H

X

L

L

H

H

H

H

H

H

H

L

L

H

4

H

X

L

H

L

L

H

L

H

H

L

L

H

H

5

H

X

L

H

L

H

H

H

L

H

H

L

H

H

6

H

X

L

H

H

L

H

L

L

H

H

H

H

H

7

H

X

L

H

H

H

H

H

H

H

L

L

L

L

8

H

X

H

L

L

L

H

H

H

H

H

H

H

H

9

H

X

H

L

L

H

H

H

H

H

L

L

H

H

10

H

X

H

L

H

L

H

L

L

L

H

H

L

H

11

H

X

H

L

H

H

H

L

L

H

H

L

L

H

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

H

X

H

H

H

H

H

L

L

L

L

L

L

L

1

BI

X

X

X

X

X

X

L

L

L

L

L

L

L

L

2

RBI

H

L

L

L

L

L

L

L

L

L

L

L

L

L

3

LT

L

X

X

X

X

X

H

H

H

H

H

H

H

H

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

5

4

3

2

1

0

6 7 8 9 101112131415

b

d

c

f

e

g