14

15

NUMERICAL DESIGNATIONS — RESULTANT DISPLAYS

0

1

2

3

4

5

6

7

8

9

10

11 12

13

NOTES:

(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=input may be HIGH

or LOW.

(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.

(3) When ripple-blanking input (RBI) and inputs A, B, C, and D are at

LOW level, with the lamp test input at HIGH level, all segment

outputs go to a HIGH level and the 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 at a HIGH level, and a LOW level is applied to lamp-test input,

all segment outputs go to a LOW level.

TRUTH TABLE

SN54 / 74LS48

INPUTS

OUTPUTS

5-60

FAST AND LS TTL DATA

SN54/74LS48

PIN NAMES

LOADING (Note a)

HIGH

LOW

A, B, C, D

RBI

LT

BI / RBO

BI

BCD Inputs

Ripple-Blanking (Active Low) Input

Lamp-Test (Active Low) Input

Blanking Input or Ripple-

Blanking Output (Active Low)

Blanking (Active Low) Input

0.5 U.L.

0.5 U.L.

0.5 U.L.

0.5 U.L.

1.2 U.L.

0.5 U.L.

Open-Collector

0.25 U.L.

0.25 U.L.

0.25 U.L.

0.75 U.L.

2(1) U.L.

0.25 U.L.

3.75 (1.25) U.L. (48)

NOTES:

a) Unit Load (U.L.) = 40

µA HIGH / 1.6 mA LOW

b) Outut current measured at VOUT = 0.5 V

Output LOW drive factor is SN54LS / 74LS48: 1.25 U.L. for Military (54), 3.75 U.L. for Commercial (74).

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

1

H

X

L

L

L

H

H

L

H

H

L

L

L

L

1

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

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