AD9838

Rev. A | Page 2 of 32

TABLE OF CONTENTS

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

 

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

 

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

 

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

 

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

 

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

 

Timing Characteristics ................................................................ 5

 

Absolute Maximum Ratings............................................................ 6

 

Thermal Resistance ...................................................................... 6

 

ESD Caution.................................................................................. 6

 

Pin Configuration and Function Descriptions............................. 7

 

Typical Performance Characteristics ............................................. 9

 

Test Circuit ...................................................................................... 12

 

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

 

Theory of Operation ...................................................................... 14

 

Circuit Description......................................................................... 15

 

Numerically Controlled Oscillator Plus Phase Modulator ... 15

 

SIN ROM ..................................................................................... 15

 

Digital-to-Analog Converter (DAC) ....................................... 15

 

Comparator ................................................................................. 15

 

Regulator...................................................................................... 16

 

Functional Description.................................................................. 17

 

Serial Interface ............................................................................ 17

 

Latency Period ............................................................................ 17

 

Control Register ......................................................................... 17

 

Frequency and Phase Registers ................................................ 19

 

Reset Function ............................................................................ 20

 

Sleep Function ............................................................................ 20

 

SIGN BIT OUT Pin.................................................................... 21

 

IOUT and IOUTB Pins ............................................................. 21

 

Powering Up the AD9838 ......................................................... 21

 

Applications Information .............................................................. 24

 

Grounding and Layout .............................................................. 24

 

Interfacing to Microprocessors................................................. 24

 

Evaluation Board ............................................................................ 26

 

System Demonstration Platform.............................................. 26

 

AD9838 to SPORT Interface..................................................... 26

 

Evaluation Kit ............................................................................. 26

 

Crystal Oscillator vs. External Clock....................................... 26

 

Power Supply............................................................................... 26

 

Evaluation Board Schematics ................................................... 27

 

Evaluation Board Layout........................................................... 29

 

Outline Dimensions ....................................................................... 30

 

Ordering Guide .......................................................................... 30

 

REVISION HISTORY

4/11—Rev. 0 to Rev. A

Change to Title.................................................................................. 1

Change to Figure 3 ........................................................................... 5

Change to Figure 8 ........................................................................... 9

4/11—Revision 0: Initial Version