Datasheet

AD7764
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 Specifications .................................................................. 6
Timing Diagrams.......................................................................... 7
Absolute Maximum Ratings ............................................................ 8
ESD Caution .................................................................................. 8
Pin Configuration and Function Descriptions ............................. 9
Typical Performance Characteristics ........................................... 11
Terminology .................................................................................... 15
Theory of Operation ...................................................................... 16
Σ-Δ Modulation and Digital Filtering ..................................... 16
AD7764 Antialias Protection .................................................... 17
AD7764 Input Structure ................................................................ 18
On-Chip Differential Amplifier ............................................... 19
Modulator Input Structure ........................................................ 20
Driving the Modulator Inputs Directly ................................... 20
AD7764 Interface............................................................................ 21
Reading Data ............................................................................... 21
Reading Status and Other Registers ......................................... 21
Writing to the AD7764 .............................................................. 21
AD7764 Functionality .................................................................... 22
Synchronization ...........................................................................22
Overrange Alerts .........................................................................22
Power Modes ................................................................................23
Decimation Rate Pin ...................................................................23
Daisy Chaining ................................................................................24
Reading Data in Daisy-Chain Mode.........................................24
Writing Data in Daisy-Chain Mode .........................................25
Clocking the AD7764 .....................................................................26
MCLK Jitter Requirements ........................................................26
Decoupling and Layout Information ............................................27
Supply Decoupling ......................................................................27
Reference Voltage Filtering ........................................................27
Differential Amplifier Components .........................................27
Layout Considerations ................................................................27
Using the AD7764 .......................................................................28
Bias Resistor Selection ................................................................28
AD7764 Registers ............................................................................29
Control Register...........................................................................29
Status Register ..............................................................................29
Gain RegisterAddress 0x0004 ................................................30
Overrange RegisterAddress 0x0005 ......................................30
Outline Dimensions ........................................................................31
Ordering Guide............................................................................31
REVISION HISTORY
11/09—Rev. 0 to Rev. A
Changes to Table 2 ............................................................................ 4
Changes to Table 3 ............................................................................ 6
Changes to Table 4 ............................................................................ 8
Changes to Typical Performance Characteristics Section,
Introductory Text............................................................................ 11
Changes to Σ-Δ Modulation and Digital Filtering Section ....... 16
Added AD7764 Antialias Protection Section ............................. 17
Changes to Figure 35 ...................................................................... 19
Added Driving the Modulator Inputs Directly Section, Including
Figure 39 and Figure 40, Renumbered Subsequent Figures ......20
Changes to Synchronization Section, Added Figure 41 .............22
Changes to Power Modes Section, Added Figure 44 ..................23
Changes to Example 2 Section .......................................................26
Changes to Using the AD7764 Section.........................................28
6/07—Revision 0: Initial Version