DM7446A, DM7447A BCD to 7-Segment Decoders/Drivers
September 1986
Revised February 2000
DM7446A, DM7447A
BCD to 7-Segment Decoders/Drivers
General Description
The DM7446A and DM7447A feature active-LOW outputs
designed for driving common-anode LEDs or incandescent
indicators directly. All of the circuits have full ripple-blank-
ing input/output controls and a lamp test input. Segment
identification and resultant displays are shown on a follow-
ing page. Display patterns for BCD input counts above nine
are unique symbols to authenticate input conditions.
All of the circuits incorporate automatic leading and/or trail-
ing-edge, zero-blanking control (RBI and RBO). Lamp test
(LT) of these devices may be performed at any time when
the BI/RBO node is at a HIGH logic level. All types contain
an overriding blanking input (BI) which can be used to con-
trol the lamp intensity (by pulsing) or to inhibit the outputs.
Features
s
All circuit types feature lamp intensity modulation capa-
bility
s
Open-collector outputs drive indicators directly
s
Lamp-test provision
s
Leading/trailing zero suppression
Ordering Code:
Order Number
DM7446AN
DM7446AN
Package Number
N16E
N16E
Package Description
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
Connection Diagram
© 2000 Fairchild Semiconductor Corporation
DS006518
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DM7446A, DM7447A
Function Table
Decimal or
Function
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
BI
RBI
LT
H
=
HIGH level,
Inputs
LT
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
X
H
L
RBI
H
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
L
X
D
L
L
L
L
L
L
L
L
H
H
H
H
H
H
H
H
X
L
X
C
L
L
L
L
H
H
H
H
L
L
L
L
H
H
H
H
X
L
X
B
L
L
H
H
L
L
H
H
L
L
H
H
L
L
H
H
X
L
X
A
L
H
L
H
L
H
L
H
L
H
L
H
L
H
L
H
X
L
X
BI/RBO
(Note 1)
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
L
L
H
a
L
H
L
L
H
L
H
L
L
L
H
H
H
L
H
H
H
H
L
b
L
L
L
L
L
H
H
L
L
L
H
H
L
H
H
H
H
H
L
c
L
L
H
L
L
L
L
L
L
L
H
L
H
H
H
H
H
H
L
Outputs
d
L
H
L
L
H
L
L
H
L
H
L
L
H
L
L
H
H
H
L
e
L
H
L
H
H
H
L
H
L
H
L
H
H
H
L
H
H
H
L
f
L
H
H
H
L
L
L
H
L
L
H
H
L
L
L
H
H
H
L
g
H
H
L
L
L
L
L
H
L
L
L
L
L
L
L
H
H
H
L
Note
(Note 2)
(Note 3)
(Note 4)
(Note 5)
L
=
LOW level,
X
=
Don’t Care
Note 1:
BI/RBO is a wire-AND logic serving as blanking input (BI) and/or ripple-blanking output (RBO).
Note 2:
The blanking input (BI) must be OPEN or held at a HIGH logic level when output functions 0 through 15 are desired. The ripple-blanking input (RBI)
must be OPEN or HIGH if blanking of a decimal zero is not desired.
Note 3:
When a LOW logic level is applied directly to the blanking input (BI), all segment outputs are HIGH regardless of the level of any other input.
Note 4:
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 H and the rip-
ple-blanking output (RBO) goes to a LOW level (response condition).
Note 5:
When the 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
L.
Logic Diagram
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2
DM7446A, DM7447A
Absolute Maximum Ratings
(Note 6)
Supply Voltage
Input Voltage
Operating Free Air Temperature Range
Storage Temperature Range
7V
5.5V
0°C to
+70°C
−65°C
to
+150°C
Note 6:
The “Absolute Maximum Ratings” are those values beyond which
the safety of the device cannot be guaranteed. The device should not be
operated at these limits. The parametric values defined in the Electrical
Characteristics tables are not guaranteed at the absolute maximum ratings.
The “Recommended Operating Conditions” table will define the conditions
for actual device operation.
Recommended Operating Conditions
Symbol
DM7446A
V
CC
V
IH
V
IL
V
OH
I
OH
I
OL
I
OL
T
A
DM7447A
V
CC
V
IH
V
IL
V
OH
I
OH
I
OL
I
OL
T
A
Supply Voltage
HIGH Level Input Voltage
LOW Level Input Voltage
HIGH Level Output Voltage (a thru g)
HIGH Level Output Current (BI/RBO)
LOW Level Output Current (a thru g)
LOW Level Output Current (BI/RBO)
Free Air Operating Temperature
0
4.75
2
0.8
15
−0.2
40
8
70
5
5.25
V
V
V
V
µA
mA
mA
°C
Supply Voltage
HIGH Level Input Voltage
LOW Level Input Voltage
HIGH Level Output Voltage (a thru g)
HIGH Level Output Current (BI/RBO)
LOW Level Output Current (a thru g)
LOW Level Output Current (BI/RBO)
Free Air Operating Temperature
0
4.75
2
0.8
30
−0.2
40
8
70
5
5.25
V
V
V
V
µA
mA
mA
°C
Parameter
Min
Nom
Max
Units
3
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DM7446A, DM7447A
DM7446A Electrical Characteristics
over recommended operating free air temperature range (unless otherwise noted)
Symbol
V
I
V
OH
I
CEX
V
OL
I
I
I
IH
I
IL
I
OS
I
CC
Parameter
Input Clamp Voltage
HIGH Level Output
Voltage (BI/RBO)
HIGH Level Output
Current (a thru g)
LOW Level
Output Voltage
Input Current @ Max
Input Voltage
HIGH Level Input
Current
LOW Level Input
Current
Short Circuit
Output Current
Supply Current
Conditions
V
CC
=
Min, I
I
= −12
mA
V
CC
=
Min
I
OH
=
Max
V
CC
=
Max, V
O
=
30V
V
IL
=
Max, V
IH
=
Min
V
CC
=
Min, I
OL
=
Max
V
IH
=
Min, V
IL
=
Max
V
CC
=
Max, V
I
=
5.5V
(Except BI/RBO)
V
CC
=
Max, V
I
=
2.4V
(Except BI/RBO)
V
CC
=
Max
V
I
=
0.4V
V
CC
=
Max
(BI/RBO)
V
CC
=
Max
(Note 8)
Note 7:
All typicals are at V
CC
=
5V, T
A
=
25°C.
Note 8:
I
CC
is measured with all outputs OPEN and all inputs at 4.5V.
Min
Typ
(Note 7)
Max
−1.5
Units
V
V
2.4
3.7
250
0.3
0.4
1
40
µA
V
mA
µA
mA
mA
mA
BI/RBO
Others
−4
−1.6
−4
60
103
DM7446A Switching Characteristics
at V
CC
=
5V and T
A
=
25°C
Symbol
t
PLH
t
PHL
Parameter
Propagation Delay Time
LOW-to-HIGH Level Output
Propagation Delay Time
HIGH-to-LOW Level Output
C
L
=
15 pF
R
L
=
120Ω
Conditions
Min
Max
100
100
Units
ns
ns
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4
DM7446A, DM7447A
DM7447A Electrical Characteristics
over recommended operating free air temperature range (unless otherwise noted)
Symbol
V
I
V
OH
I
CEX
V
OL
I
I
I
IH
I
IL
I
OS
I
CC
Parameter
Input Clamp Voltage
HIGH Level Output
Voltage (BI/RBO)
HIGH Level Output
Current (a thru g)
LOW Level Output
Voltage
Input Current @ Max
Input Voltage
HIGH Level Input Current
LOW Level Input
Current
Short Circuit
Output Current
Supply Current
V
CC
=
Max, V
I
=
2.4V
V
CC
=
Max
V
I
=
0.4V
V
CC
=
Max
(BI/RBO)
V
CC
=
Max
(Note 10)
Note 9:
All typicals are at V
CC
=
5V, T
A
=
25°C.
Note 10:
I
CC
is measured with all outputs OPEN and all inputs at 4.5V.
Conditions
V
CC
=
Min, I
I
= −12
mA
V
CC
=
Min
I
OH
=
Max
V
CC
=
Max, V
O
=
15V
V
IL
=
Max, V
IH
=
Min
V
CC
=
Min, I
OL
=
Max
V
IH
=
Min, V
IL
=
Max
V
CC
=
Max, V
I
=
5.5V
Min
Typ
(Note 9)
Max
−1.5
Units
V
V
2.4
3.7
250
0.3
0.4
1
40
µA
V
mA
µA
mA
mA
mA
BI/RBO
Others
−4
−1.6
−4
60
103
DM7447A Switching Characteristics
at V
CC
=
5V and T
A
=
25°C
Symbol
t
PLH
t
PHL
Parameter
Propagation Delay Time
LOW-to-HIGH Level Output
Propagation Delay Time
HIGH-to-LOW Level Output
C
L
=
15 pF
R
L
=
120Ω
Conditions
Min
Max
100
100
Units
ns
ns
5
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