AD7938/AD7939

Data Sheet

Rev. C | Page 2 of 36

TABLE OF CONTENTS

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

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

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

Product Highlights ........................................................................... 1

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

Specifications..................................................................................... 3

AD7938 Specifications................................................................. 3

AD7939 Specifications................................................................. 5

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

Absolute Maximum Ratings............................................................ 8

ESD Caution.................................................................................. 8

Pin Configuration and Function Descriptions............................. 9

Typical Performance Characteristics ........................................... 11

Terminology .................................................................................... 13

On-Chip Registers.......................................................................... 15

Control Register.......................................................................... 15

Sequencer Operation ................................................................. 16

Shadow Register.......................................................................... 17

Circuit Information........................................................................ 18

Converter Operation.................................................................. 18

ADC Transfer Function............................................................. 18

Typical Connection Diagram ................................................... 19

Analog Input Structure.............................................................. 19

Analog Inputs.............................................................................. 20

Analog Input Selection .............................................................. 22

Reference ..................................................................................... 23

Parallel Interface......................................................................... 25

Power Modes of Operation....................................................... 28

Power vs. Throughput Rate....................................................... 29

Microprocessor Interfacing....................................................... 29

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

Grounding and Layout .............................................................. 31

PCB Design Guidelines for Chip Scale Package .................... 31

Evaluating AD7938/AD7939 Performance ............................ 31

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

Ordering Guide .......................................................................... 33

REVISION HISTORY

10/11—Rev. B to Rev. C

Changes to SINAD Specification in Features Section ................. 1

Changes to AD7938 Specifications Section .................................. 3

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

Changes to Ordering Guide .......................................................... 33

2/07—Rev. A to Rev. B

Updated Format..................................................................Universal

Changes to Sequencer Operation Section................................... 16

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

7/05—Rev. 0 to Rev. A

Changes to Specifications................................................................ 3

Added Figure 3.................................................................................. 9

Changes to Table 5.......................................................................... 10

Updated Typical Performance Characteristics ........................... 13

Changes to Table 11........................................................................ 16

Changes to Analog Input Structure Section ............................... 18

Changes to Analog Inputs Section............................................... 19

Changes to Figure 17...................................................................... 17

Changes to Figure 20...................................................................... 18

Changes to Figure 21...................................................................... 19

Changes to Figure 22...................................................................... 19

Changes to Figure 24...................................................................... 19

Changes to Figure 28...................................................................... 21

Changes to Figure 29...................................................................... 21

Changes to Figure 41...................................................................... 28

Changes to Figure 43...................................................................... 28

Changes to Figure 44...................................................................... 29

Changes to Figure 45...................................................................... 29

Changes to Figure 46...................................................................... 29

Updated Outline Dimensions....................................................... 31

Changes to Ordering Guide.......................................................... 32

10/04—Revision 0: Initial Version