National Semiconductor DM74184, DM74185A Technical data

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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 con­nections 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 illus­trated in the typical applications. This means that a 6-bit
converter is produced in each case. Both devices are cas­cadable to N bits.

An overriding enable input is provided on each converter
which when taken high inhibits the function, causing all out­puts 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.

DM74184 BCD-TO-BINARY CONVERTERS

The 6-bit BCD-to-binary function of the DM74184 is analo­gous to the algorithm:

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.

DM74184/DM74185A BCD-to-Binary and Binary-to-BCD Converters

June 1989

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 comple­ment code is logically equal to one of the BCD bits; there­fore, these complements can be produced on three lines.
As outputs Y6, Y7 and Y8 are not required in the BCD-to-bi­nary conversion, they are utilized to provide these comple­ment codes as specified in the function table when the de­vices are connected as shown.

DM74185A BINARY-TO-BCD CONVERTERS

The function performed by these 6-bit binary-to-BCD con­verters 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.

c. Repeat step b until the least-significant binary bit is in the

least-significant BCD location.

(Continued)

Connection Diagram

Order Number DM74184N or DM74185AN

See NS Package Number N16E

C

1995 National Semiconductor Corporation RRD-B30M105/Printed in U. S. A.

TL/F/6561

TL/F/6561– 1

Absolute Maximum Ratings (Note)

Note:

If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales
Office/Distributors for availability and specifications.

Supply Voltage 7V

Input Voltage 5.5V

Output Voltage 7V

Operating Free Air Temperature

Range 0

Storage Temperature Range

Ctoa70§C

§

b

65§Ctoa150§C

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’’
table 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 Parameter Min Nom Max Units

V

CC

V

IH

V

IL

V

OH

I

OL

T

A

Supply Voltage 4.75 5 5.25 V

High Level Input Voltage 2 V

Low Level Input Voltage 0.8 V

High Level Output Voltage 5.5 V

Low Level Output Current 12 mA

Free Air Operating Temperature 0 70

’184 and ’185A Electrical Characteristics

over recommended operating free air temperature range (unless otherwise noted)

Symbol Parameter Conditions Min

e

e

Max, V

e

Min, V

e

e

e

e

e

Min, I

Min, V

Min, I

Max, V

Max, V

Max, V

Max

Max

eb

12 mA

I

e

5.5V

O

e

Min

IH

e

Max

OL

e

Max

IL

e

5.5V

I

e

2.4V 25 mA

I

e

0.4V

I

V

I

I

CEX

V

OL

I

I

I

IH

I

IL

I

CCH

I

CCL

Input Clamp Voltage V

High Level Output V
Current V

Low Level Output V
Voltage V

Input Current@Max V
Input Voltage

High Level Input Current V

Low Level Input Current V

Supply Current with V
Outputs High

Supply Current with V
Outputs Low

CC

CC
IL

CC
IH

CC

CC

CC

CC

CC

e

e

Typ

(Note 1)

Max Units

b

1.5 V

100 mA

0.4 V

1mA

b

1mA

65 95 mA

80 99 mA

C

§

’184 and ’185A Switching Characteristics

e

at V

CC

5V and T

Symbol Parameter To (Output)

t

PLH

t

PHL

t

PLH

t

PHL

Note 1: All typicals are at V

e

25§C (See Section 1 for Test Waveforms and Output Load)

A

From (Input)

Propagation Delay Time Enable G
Low to High Level Output to Output

Propagation Delay Time Enable G
High to Low Level Output to Output

Propagation Delay Time Binary Select
Low to High Level Output to Output

Propagation Delay Time Binary Select
High to Low Level Output to Output

e

e

5V, T

CC

25§C.

A

2

e

400X,R

R

L1

e

15 pF (See Test Circuit)

C

L

e

L2

Min Max

600X

Units

35 ns

35 ns

35 ns

35 ns

General Description (Continued)

TABLE I. Package Count and Delay Times

Input Packages Total Delay Times (ns)

(Decades) Required

2 2 56 80
3 6 140 200
4 12 196 280
5 19 280 400
6 28 364 520

DM74184 BCD-to-Binary

for BCD-to-Binary Conversion

Typ Max

6-Bit Converter

BCD 9’s

Complement Converter

TL/F/6561– 2

DM74185A Binary-to-BCD

TABLE II. Package Count and Delay Times

for Binary-to-BCD Conversion

Input Packages Total Delay Times (ns)
(Bits) Required

Typ Max

4to6 1 25 40
7or8 3 50 80

9 4 75 120
10 6 100 160
11 7 125 200
12 8 125 200
13 10 150 240
14 12 175 280
15 14 175 280
16 16 200 320
17 19 225 360
18 21 225 360
19 24 250 400
20 27 275 440

TL/F/6561– 3

BCD’s 10’s

Complement Converter

TL/F/6561– 4

6-Bit Converter

TL/F/6561– 5

3

Function Tables

Binary
Words Binary Select Enable

EDCBA G Y8Y7Y6Y5Y4Y3Y2Y1

01LLLLL L HHLLLLLL
23LLLLH L HHLLLLLH
45LLLHL L HHLL LLHL
67LLLHH L HHLLLLHH

89LLHLL L HHLL LHLL
10 11 L L H L H L H H L L H L L L
1213LLHHL L HHLLHLLH
1415LLHHH L HHLLHLHL

1617LHLLL L HHLLHLHH
1819LHLLH L HHLLHHLL
2021LHLHL L HHLHLLLL
22 23 L H L H H L H H L H L L L H

2425LHHLL L HHLHLLHL
2627LHHLH L HHLHLLHH
2829LHHHL L HHLHLHLL
30 31 L H H H H L H H L H H L L L

3233HLLLL L HHLHHLLH
3435HLLLH L HHLHHLHL
3637HLLHL L HHLHHLHH
38 39 H L L H H L H H L H H H L L

4041HLHLL L HHHLLLLL
4243HLHLH L HHHLLLLH
4445HLHHL L H H H L L L H L
4647HLHHH L HHHL L LHH

48 49 H H L L L L H H H L L H L L
50 51 H H L L H L H H H L H L L L
5253HHLHL L HHHLHLLH
5455HHLHH L HHHLHLHL

5657HHHLL L HHHLHLHH
5859HHHLH L HHHLHHL L
6061HHHHL L HHHHLLLL
6263HHHHH L HHHH L L L H

All XXXXX H HHHHHHHH

Inputs Outputs

4

Function Tables (Continued)

BCD-to-Binary Converter

BCD

Words

Inputs Outputs

(See Note A) (See Note B)

EDCBAGY5Y4Y3Y2Y1

0 1 LLLLLL L L L L L
2 3 LLLLHL L L L L H
4 5 LLLHL L L L L H L
67LLLHHLLLLHH
89LLHLLLLLHLL

10 11 L H L L L L L L H L H
12 13 L H L L H L L L H H L
14 15 LHLHLL L L H H H
16 17 L H L H H L L H L L L
18 19 L H H L L L L H L L H

20 21 H L L L L L L H L H L
22 23 H L L L H L L H L H H
24 25 HL LHLL L H H L L
26 27 HLLHHLLHHLH
28 29 H L H L L L L H H H L

30 31 H H L L L L L H H H H
32 33 H H L L H L H L L L L
34 35 H H L H L L H L L L H
36 37 HHLHHLHL LHL
38 39 H H H L L L H L L H H

Any XXXXXH H H H H H

HeHigh Level, LeLow Level, XeDon’t Care

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.

BCD 9’s or BCD 10’s Complement Converter

BCD

Word

Inputs Outputs

(See Note C) (See Note D)

E²DCBAGY8Y7Y6

0 L LLLLL H L H
1 L LLLHL H L L
2 L LLHLL L H H
3 LLLHHLLHL
4 L LHLLL L H H

5 L LHLHL L H L
6 L LHHLL L L H
7 L L HHHL L L L
8 L HLLLL L L H
9 L HL LHL L L L

0 H LLLLL L L L
1 H LLLHL H L L
2 H L LHL L H L L
3HLLHHLLHH
4 H LHL L L L H H

5 H LHLHL L H L
6 H LHHLL L H L
7 H LHHHL L L H
8 HHLLLL L L H
9 H HLLHL L L L

Any X XXXXH H H H

Test Circuit

CLincludes probe and jig capacitance

TL/F/6561– 6

Typical Applications

FIGURE 1. BCD-to-Binary Converter

MSDÐMost significant decade
LSDÐLeast significant decade
Each rectangle represents a DM74184

5

for Two BCD Decades

TL/F/6561– 7

Typical Applications (Continued)

MSDÐMost significant decade
LSDÐLeast significant decade
Each rectangle represents a DM74184

FIGURE 2. BCD-to-Binary Converter for Six BCD Decades

TL/F/6561– 9

6

Typical Applications (Continued)

FIGURE 3. BCD-to-Binary Converter

for Three BCD Decades

MSDÐMost significant decade
LSDÐLeast significant decade
Each rectangle represents a DM74184

TL/F/6561– 8

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– 10

FIGURE 5. 8-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– 11

FIGURE 6. 9-Bit Binary-to-BCD Converter

TL/F/6561– 12

MSDÐMost significant decade

LSDÐLeast significant decade

Note A: Each rectangle represents a DM74185A.

Note B: All unused E inputs are grounded.

7

Typical Applications (Continued)

FIGURE 7. 12-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.

TL/F/6561– 13

TL/F/6561– 14

FIGURE 8. 16-Bit Binary-to-BCD Converter (See Note B)

8

9

Physical Dimensions inches (millimeters)

16-Lead Molded Dual-In-Line Package (N)
Order Number DM74184N or DM74185AN

NS Package Number N16E

DM74184/DM74185A BCD-to-Binary and Binary-to-BCD Converters

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