AD7682/AD7689

Data Sheet

Rev. D | Page 2 of 32

TABLE OF CONTENTS

Features .............................................................................................. 1

 

Applications....................................................................................... 1

 

Functional Block Diagram .............................................................. 1

 

General Description ......................................................................... 1

 

Revision History ............................................................................... 2

 

Specifications..................................................................................... 4

 

Timing Specifications .................................................................. 7

 

Absolute Maximum Ratings............................................................ 9

 

ESD Caution.................................................................................. 9

 

Pin Configurations and Function Descriptions ......................... 10

 

Typical Performance Characteristics ........................................... 12

 

Terminology .................................................................................... 15

 

Theory of Operation ...................................................................... 16

 

Overview...................................................................................... 16

 

Converter Operation.................................................................. 16

 

Transfer Functions...................................................................... 17

 

Typical Connection Diagrams.................................................. 18

 

Analog Inputs.............................................................................. 19

 

Driver Amplifier Choice............................................................ 21

 

Voltage Reference Output/Input .............................................. 21

 

Power Supply............................................................................... 23

 

Supplying the ADC from the Reference.................................. 23

 

Digital Interface .............................................................................. 24

 

Reading/Writing During Conversion, Fast Hosts.................. 24

 

Reading/Writing After Conversion, Any Speed Hosts.......... 24

 

Reading/Writing Spanning Conversion, Any Speed Host.... 24

 

Configuration Register, CFG .................................................... 24

 

General Timing Without a Busy Indicator ............................. 26

 

General Timing with a Busy Indicator .................................... 27

 

Channel Sequencer .................................................................... 28

 

Read/Write Spanning Conversion Without a Busy Indicator

....................................................................................................... 29

 

Read/Write Spanning Conversion with a Busy Indicator..... 30

 

Application Hints ........................................................................... 31

 

Layout .......................................................................................... 31

 

Evaluating AD7682/AD7689 Performance ............................ 31

 

Outline Dimensions ....................................................................... 32

 

Ordering Guide .......................................................................... 32

 

REVISION HISTORY

4/12—Rev. C to Rev. D

Changes to Figure 27...................................................................... 18

Changed Internal Reference Section to Internal

Reference/Temperature Sensor Section....................................... 21

Changes to Internal Reference/Temperature Sensor Section ... 21

Changed External Reference/Temperature Sensor Section to

External Reference Section............................................................ 22

Changes to External Reference and Internal Buffer Section and

External Reference Section............................................................ 22

Changes to REF Bit, Function Column, Table 10 ...................... 25

Updated Outline Dimensions ....................................................... 32

9/11—Rev. B to Rev. C

Changes to Internal Reference Section........................................ 21

Changes to the External Reference and Internal Buffer

Section.............................................................................................. 22

Changes to the External Reference/Temperature Sensor

Section.............................................................................................. 22

Changes to Table 10, REF Bit Description .................................. 25

6/09—Rev. A to Rev. B

Changes Table 6 ................................................................................ 8

Changes to Figure 37...................................................................... 25

Changes to Figure 38...................................................................... 26

3/09—Rev. 0 to Rev. A

Changes to Features Section, Applications Section, and

Figure 1 ...............................................................................................1

Added Table 2; Renumbered Sequentially .....................................3

Changes to Table 3.............................................................................5

Changes to Table 4.............................................................................6

Changes to Table 5.............................................................................7

Deleted Endnote 2 in Table 6...........................................................8

Changes to Figure 4, Figure 5, and Table 7 ....................................9

Changes to Figure 6, Figure 9, and Figure 10 ............................. 11

Changes to Figure 22...................................................................... 13

Changes to Overview Section and Converter Operation

Section.............................................................................................. 15

Changes to Table 8.......................................................................... 16

Changes to Figure 26 and Figure 27............................................. 17

Changes to Bipolar Single Supply Section and Analog Inputs

Section.............................................................................................. 18

Changes to Internal Reference/Temperature Sensor Section ... 20

Added Figure 31; Renumbered Sequentially .............................. 20

Changes to External Reference and Internal Buffer Section and

External Reference Section ........................................................... 21

Added Figure 32 and Figure 33 .................................................... 21

Changes to Power Supply Section ................................................ 22