74185 [NSC]
BCD-to-Binary and Binary-to-BCD Converters; BCD到二进制和二进制到BCD转换器
| 型号： | 74185 |
| 厂家： | 
National Semiconductor |
| 描述： | BCD-to-Binary and Binary-to-BCD Converters |
| 文件： | 总10页 (文件大小：179K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
June 1989
DM74184/DM74185A
BCD-to-Binary and Binary-to-BCD Converters
General Description
These monolithic converters are derived from the 256-bit
read only memories, DM5488, and DM7488. Emitter con-
nections are made to provide direct read-out of converted
codes at outputs Y8 through Y1, as shown in the function
tables. These converters demonstrate the versatility of a
read only memory in that an unlimited number of reference
tables or conversion tables may be built into a system. Both
of these converters comprehend that the least significant
bits (LSB) of the binary and BCD codes are logically equal,
and in each case the LSB bypasses the converter as illus-
trated in the typical applications. This means that a 6-bit
converter is produced in each case. Both devices are cas-
cadable to N bits.
b. Shift right, examine, and correct after each shift until the
least significant decade contains a number smaller than
eight and all other converted decades contain zeros.
In addition to BCD-to-binary conversion, the DM74184 is
programmed to generate BCD 9’s complement or BCD 10’s
complement. Again, in each case, one bit of the comple-
ment code is logically equal to one of the BCD bits; there-
fore, these complements can be produced on three lines.
As outputs Y6, Y7 and Y8 are not required in the BCD-to-bi-
nary conversion, they are utilized to provide these comple-
ment codes as specified in the function table when the de-
vices are connected as shown.
DM74185A BINARY-TO-BCD CONVERTERS
An overriding enable input is provided on each converter
which when taken high inhibits the function, causing all out-
puts to go high. For this reason, and to minimize power
consumption, unused outputs Y7 and Y8 of the 185A and all
‘‘don’t care’’ conditions of the 184 are programmed high.
The outputs are of the open-collector type.
The function performed by these 6-bit binary-to-BCD con-
verters is analogous to the algorithm:
a. Examine the three most significant bits. If the sum is
greater than four, add three and shift left one bit.
b. Examine each BCD decade. If the sum is greater than
four, add three and shift left one bit.
DM74184 BCD-TO-BINARY CONVERTERS
c. Repeat step b until the least-significant binary bit is in the
least-significant BCD location.
The 6-bit BCD-to-binary function of the DM74184 is analo-
gous to the algorithm:
(Continued)
a. Shift BCD number right one bit and examine each dec-
ade. Subtract three from each 4-bit decade containing a
binary value greater than seven.
Connection Diagram
TL/F/6561–1
Order Number DM74184N or DM74185AN
See NS Package Number N16E
C
1995 National Semiconductor Corporation
TL/F/6561
RRD-B30M105/Printed in U. S. A.
Absolute Maximum Ratings (Note)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales
Office/Distributors for availability and specifications.
Note: The ‘‘Absolute Maximum Ratings’’ are those values
beyond which the safety of the device cannot be guaran-
teed. The device should not be operated at these limits. The
parametric values defined in the ‘‘Electrical Characteristics’’
table are not guaranteed at the absolute maximum ratings.
The ‘‘Recommended Operating Conditions’’ table will define
the conditions for actual device operation.
Supply Voltage
Input Voltage
Output Voltage
7V
5.5V
7V
Operating Free Air Temperature
Range
a
0 C to 70 C
§
§
b
a
65 C to 150 C
Storage Temperature Range
§
§
Recommended Operating Conditions
Symbol
Parameter
Min
4.75
2
Nom
Max
Units
V
V
V
V
V
Supply Voltage
5
5.25
CC
High Level Input Voltage
Low Level Input Voltage
V
IH
0.8
5.5
12
V
IL
High Level Output Voltage
Low Level Output Current
Free Air Operating Temperature
V
OH
I
mA
OL
T
A
0
70
C
§
’184 and ’185A Electrical Characteristics
over recommended operating free air temperature range (unless otherwise noted)
Typ
(Note 1)
Symbol
Parameter
Conditions
e b
Min
Max
Units
e
e
b
1.5
V
I
Input Clamp Voltage
V
Min, I
I
12 mA
V
CC
e
e
I
High Level Output
Current
V
V
Min, V
5.5V
Min
CEX
CC
O
100
0.4
mA
e
Max, V
IL
IH
e
e
V
OL
Low Level Output
Voltage
V
CC
V
IH
Min, I
OL
Min, V
Max
Max
V
e
e
IL
@
Input Current Max
Input Voltage
e
e
I
V
CC
Max, V
5.5V
I
I
1
mA
e
e
e
e
e
I
I
I
High Level Input Current
Low Level Input Current
V
V
V
Max, V
Max, V
Max
2.4V
0.4V
25
mA
IH
CC
CC
CC
I
b
1
mA
IL
I
Supply Current with
Outputs High
CCH
65
80
95
99
mA
mA
e
I
Supply Current with
Outputs Low
V
CC
Max
CCL
’184 and ’185A Switching Characteristics
5V and T
e
e
25 C (See Section 1 for Test Waveforms and Output Load)
at V
§
CC
A
e
e
600X
15 pF (See Test Circuit)
R
400X, R
L1
L2
From (Input)
To (Output)
e
C
L
Symbol
Parameter
Units
Min
Max
t
t
t
t
Propagation Delay Time
Low to High Level Output
Enable G
to Output
PLH
PHL
PLH
PHL
35
35
35
35
ns
ns
ns
ns
Propagation Delay Time
High to Low Level Output
Enable G
to Output
Propagation Delay Time
Low to High Level Output
Binary Select
to Output
Propagation Delay Time
High to Low Level Output
Binary Select
to Output
e
e
25 C.
Note 1: All typicals are at V
5V, T
§
CC
A
2
General Description (Continued)
DM74184 BCD-to-Binary
TABLE I. Package Count and Delay Times
for BCD-to-Binary Conversion
Input
Packages
Total Delay Times (ns)
(Decades) Required
Typ
Max
2
3
4
5
6
2
56
80
6
140
196
280
364
200
280
400
520
12
19
28
6-Bit Converter
BCD 9’s
Complement Converter
BCD’s 10’s
Complement Converter
TL/F/6561–2
TL/F/6561–4
TL/F/6561–3
DM74185A Binary-to-BCD
TABLE II. Package Count and Delay Times
for Binary-to-BCD Conversion
Input
(Bits)
Packages
Required
Total Delay Times (ns)
Typ
Max
6-Bit Converter
4 to 6
7 or 8
9
1
3
25
40
50
80
4
75
120
160
200
200
240
280
280
320
360
360
400
440
10
6
100
125
125
150
175
175
200
225
225
250
275
11
7
12
8
13
10
12
14
16
19
21
24
27
14
15
16
17
TL/F/6561–5
18
19
20
3
Function Tables
Inputs
B
Outputs
Binary
Words
Binary Select
Enable
G
E
D
C
A
Y8
Y7
Y6
Y5
Y4
Y3
Y2
Y1
0
1
3
5
7
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
H
L
L
L
L
L
H
H
H
H
H
H
H
H
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
H
L
2
4
6
H
H
H
H
H
H
8
9
L
L
L
L
L
L
L
L
H
H
H
H
L
L
L
H
L
L
L
L
L
H
H
H
H
H
H
H
H
L
L
L
L
L
L
L
L
L
H
H
H
H
L
L
L
L
L
L
L
10
12
14
11
13
15
H
H
L
H
L
H
H
16
18
20
22
17
19
21
23
L
L
L
L
H
H
H
H
L
L
L
L
L
L
L
H
L
L
L
L
L
H
H
H
H
H
H
H
H
L
L
L
L
L
L
H
H
L
L
H
L
H
L
L
L
H
L
H
H
H
H
L
H
L
L
H
24
26
28
30
25
27
29
31
L
L
L
L
H
H
H
H
H
H
H
H
L
L
L
H
L
L
L
L
L
H
H
H
H
H
H
H
H
L
L
L
L
H
H
H
H
L
L
L
L
H
H
L
L
H
L
H
H
L
H
L
H
H
L
L
32
34
36
38
33
35
37
39
H
H
H
H
L
L
L
L
L
L
L
L
L
L
L
H
L
L
L
L
L
H
H
H
H
H
H
H
H
L
L
L
L
H
H
H
H
H
H
H
H
L
L
L
H
H
L
H
L
H
H
L
H
L
H
H
40
42
44
46
41
43
45
47
H
H
H
H
L
L
L
L
H
H
H
H
L
L
L
H
L
L
L
L
L
H
H
H
H
H
H
H
H
H
H
H
H
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
H
L
H
H
H
H
H
H
48
50
52
54
49
51
53
55
H
H
H
H
H
H
H
H
L
L
L
L
L
L
L
H
L
L
L
L
L
H
H
H
H
H
H
H
H
H
H
H
H
L
L
L
L
L
H
H
H
H
L
L
L
L
L
L
L
H
H
L
H
L
H
H
56
58
60
62
57
59
61
63
H
H
H
H
H
H
H
H
H
H
H
H
L
L
L
H
L
L
L
L
L
H
H
H
H
H
H
H
H
H
H
H
H
L
L
H
H
L
L
H
L
H
L
L
L
H
L
H
H
H
H
L
H
L
L
H
All
X
X
X
X
X
H
H
H
H
H
H
H
H
H
4
Function Tables (Continued)
BCD-to-Binary Converter
BCD 9’s or BCD 10’s Complement Converter
Inputs
BCD
(See Note A)
Outputs
Inputs
Outputs
BCD
(See Note B)
(See Note C)
(See Note D)
Words
Word
²
E
D
C
B
A
G
Y5 Y4 Y3 Y2 Y1
E
D
C
B
A
G
Y8
Y7
Y6
0
1
3
5
7
9
L
L
L
L
L
L
L
L
L
L
L
L
L
L
H
L
L
L
H
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
H
L
L
L
H
L
0
1
2
3
4
L
L
L
L
L
L
L
L
L
L
H
L
L
L
H
L
L
L
L
L
L
H
H
L
L
L
H
L
2
4
6
8
L
L
L
L
H
H
L
H
H
L
H
H
L
H
H
H
H
L
H
L
H
L
H
L
L
L
H
10
12
14
16
18
11
13
15
17
19
L
L
L
L
L
H
H
H
H
H
L
L
L
L
H
L
L
L
H
L
L
L
L
L
L
L
L
L
L
L
L
L
H
H
H
L
L
H
H
L
H
L
5
6
7
8
9
L
L
L
L
L
L
L
H
H
H
L
L
H
H
L
H
L
L
L
L
L
L
L
L
L
L
L
H
L
L
L
L
L
H
L
H
H
L
L
H
L
L
H
L
H
L
H
H
H
H
H
L
L
L
H
L
L
H
20
22
24
26
28
21
23
25
27
29
H
H
H
H
H
L
L
L
L
L
L
L
L
L
H
L
L
L
H
L
L
L
L
L
L
L
L
L
L
L
H
H
H
H
H
L
L
H
H
L
L
H
L
0
1
2
3
4
H
H
H
H
H
L
L
L
L
L
L
L
L
L
H
L
L
L
H
L
L
L
L
L
L
L
H
H
L
L
L
L
L
H
H
L
H
H
H
H
H
L
L
L
H
L
L
H
L
H
L
H
H
H
H
H
L
30
32
34
36
38
31
33
35
37
39
H
H
H
H
H
H
H
H
H
H
L
L
L
L
H
L
L
L
H
L
L
L
L
L
L
L
H
L
L
L
L
H
L
L
L
L
H
L
H
L
5
6
7
8
9
H
H
H
H
H
L
L
H
H
H
L
L
H
H
L
H
L
L
L
L
L
L
L
L
L
L
L
H
H
L
L
L
H
H
H
H
H
H
L
L
H
L
L
H
L
H
H
L
H
L
H
H
H
H
L
H
L
L
H
L
Any
X
X
X
X
X
H
H
H
H
H
H
Any
X
X
X
X
X
H
H
H
H
e
e
e
Low Level, X Don’t Care
H
High Level, L
Note A: Input Conditions other than those shown produce highs at outputs Y1 through Y5.
Note B: Output Y6, Y7, and Y8 are not used for BCD-to-Binary conversion.
Note C: Input conditions other than those shown produce highs at outputs Y6, Y7, and Y8.
Note D: Outputs Y1 through Y5 are not used for BCD 9’s or BCD 10’s complement conversion.
²
When these devices are used as complement converters, input E is used as a mode control. With this input low, the BCD 9’s complement is generated; when it is
high, the BCD 10’s complement is generated.
Test Circuit
Typical Applications
TL/F/6561–6
C
L
includes probe and jig capacitance
TL/F/6561–7
FIGURE 1. BCD-to-Binary Converter
for Two BCD Decades
MSDÐMost significant decade
LSDÐLeast significant decade
Each rectangle represents a DM74184
5
Typical Applications (Continued)
TL/F/6561–9
FIGURE 2. BCD-to-Binary Converter for Six BCD Decades
MSDÐMost significant decade
LSDÐLeast significant decade
Each rectangle represents a DM74184
6
Typical Applications (Continued)
TL/F/6561–10
FIGURE 4. 6-Bit Binary-to-BCD Converter
MSDÐMost significant decade
LSDÐLeast significant decade
Note A: Each rectangle represents a DM74185A.
Note B: All unused E inputs are grounded.
TL/F/6561–8
FIGURE 3. BCD-to-Binary Converter
for Three BCD Decades
MSDÐMost significant decade
LSDÐLeast significant decade
Each rectangle represents a DM74184
TL/F/6561–11
TL/F/6561–12
FIGURE 5. 8-Bit Binary-to-BCD Converter
FIGURE 6. 9-Bit Binary-to-BCD Converter
MSDÐMost significant decade
MSDÐMost significant decade
LSDÐLeast significant decade
LSDÐLeast significant decade
Note A: Each rectangle represents a DM74185A.
Note B: All unused E inputs are grounded.
Note A: Each rectangle represents a DM74185A.
Note B: All unused E inputs are grounded.
7
Typical Applications (Continued)
TL/F/6561–13
FIGURE 7. 12-Bit Binary-to-BCD
Converter (See Note B)
TL/F/6561–14
FIGURE 8. 16-Bit Binary-to-BCD Converter (See Note B)
MSDÐMost significant decade
LSDÐLeast significant decade
Note A: Each rectangle represents a DM74185A.
Note B: All unused E inputs are grounded.
8
9
Physical Dimensions inches (millimeters)
16-Lead Molded Dual-In-Line Package (N)
Order Number DM74184N or DM74185AN
NS Package Number N16E
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