SN54/74LS48
PIN NAMES
LOADING (Note a)
HIGH
LOW
A, B, C, D
RBI
LT
BCD Inputs
0.5 U.L.
0.5 U.L.
0.5 U.L.
0.25 U.L.
0.25 U.L.
0.25 U.L.
0.75 U.L.
Ripple-Blanking (Active Low) Input
Lamp-Test (Active Low) Input
Blanking Input or Ripple-
BI/RBO
0.5 U.L.
Blanking Output (Active Low)
Blanking (Active Low) Input
1.2 U.L.
0.5 U.L.
2(1) U.L.
0.25 U.L.
BI
Open-Collector
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 V = 0.5 V
OUT
Output LOW drive factor is SN54LS/74LS48: 1.25 U.L. for Military (54), 3.75 U.L. for Commercial (74).
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15
NUMERICAL DESIGNATIONS — RESULTANT DISPLAYS
TRUTH TABLE
SN54/74LS48
INPUTS
OUTPUTS
DECIMAL
OR
LT
RBI
D
C
B
A
BI /RBO
a
b
c
d
e
f
g
NOTE
FUNCTION
0
1
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
X
H
L
H
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
L
L
L
L
L
L
L
L
H
L
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
L
H
L
H
H
H
H
H
L
H
H
L
H
L
H
L
H
L
L
L
1
1
2
L
L
H
H
L
H
H
L
H
H
L
H
L
L
H
H
H
H
H
L
NOTES:
3
L
L
H
L
H
H
H
H
H
H
H
L
L
(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)
allsegmentoutputsgotoaLOWlevel, regardlessofthestateofany
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.
4
L
H
H
H
H
L
L
H
H
H
L
5
L
L
H
L
H
L
H
H
L
L
6
L
H
H
L
L
H
L
7
L
H
L
H
H
H
L
H
H
H
L
8
H
H
H
H
H
H
H
H
X
L
H
L
H
L
H
H
L
H
H
H
H
H
H
H
L
9
L
L
H
L
10
11
12
13
14
15
BI
RBI
LT
L
H
H
L
H
H
L
H
L
L
H
L
L
L
H
L
L
H
H
H
H
X
L
L
H
L
L
H
H
H
L
L
H
L
H
L
L
H
H
L
L
H
H
X
L
L
L
H
L
H
X
L
L
L
L
L
L
L
L
L
L
L
2
3
4
L
L
L
L
L
L
L
L
X
X
X
X
X
H
H
H
H
H
H
H
H
FAST AND LS TTL DATA
5-60
MOTOROLA [ MOTOROLA ]
