Datasheet

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