Datasheet AD7944 (Analog Devices) - 3

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AD7944 Data Sheet TABLE OF CONTENTS
Features .. 1 Analog Inputs ... 15 Applications ... 1 Driver Amplifier Choice ... 15 General Description ... 1 Voltage Reference Input .. 16 Application Diagram .. 1 Power Supply ... 16 Revision History ... 2 Digital Interface .. 17 Specifications ... 3 Data Reading Options ... 18 Timing Specifications .. 5 CS Mode, 3-Wire Without Busy Indicator ... 19 Absolute Maximum Ratings .. 6 CS Mode, 3-Wire with Busy Indicator .. 20 ESD Caution .. 6 CS Mode, 4-Wire Without Busy Indicator ... 21 Pin Configuration and Function Descriptions ... 7 CS Mode, 4-Wire with Busy Indicator .. 22 Typical Performance Characteristics ... 9 Chain Mode Without Busy Indicator .. 23 Terminology .. 12 Chain Mode with Busy Indicator ... 24 Theory of Operation .. 13 Applications Information .. 25 Circuit Information .. 13 Layout .. 25 Converter Operation .. 13 Evaluating AD7944 Performance ... 25 Conversion Modes of Operation .. 13 Outline Dimensions ... 27 Typical Application Diagram .. 14 Ordering Guide .. 27
REVISION HISTORY 2/16—Rev. B to Rev. C
Changes to Table 1 .. 1
7/14—Rev. A to Rev. B
Change to Transition Noise Parameter, Table 2 ... 3 Changes to Features Section .. 1 Deleted Note 4, Table 2 .. 3 Added Patent Note, Note 1 ... 1 Changes to Figure 4 .. 7 Changes to Figure 21.. 13 Changed Typical Connection Diagram Section to Typical Changes to Data Reading Options Section ... 18 Application Diagram Section .. 14 Change to Typical Application Diagram Section ... 14
8/10—Rev. 0 to Rev. A
Changes to Figure 23 .. 14 Changes to Table 4, Conversion Time: CNV Rising Edge Changes to Driver Amplifier Choice Section ... 15 to Data Available .. 5 Change to Reference Decoupling Section ... 16 Changes to Reading During Conversion, Fast Host (Turbo
10/09—Revision 0: Initial Version
or Normal Mode) Section and Split Reading, Any Speed Host (Turbo or Normal Mode) Section .. 18 Changes to Figure 31 .. 21 Changes to Evaluating AD7944 Performance Section .. 25 Updated Outline Dimensions ... 27 Changes to Ordering Guide .. 27 Rev. C | Page 2 of 28 Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION APPLICATION DIAGRAM TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS TIMING SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS TERMINOLOGY THEORY OF OPERATION CIRCUIT INFORMATION CONVERTER OPERATION CONVERSION MODES OF OPERATION Transfer Functions TYPICAL APPLICATION DIAGRAM ANALOG INPUTS DRIVER AMPLIFIER CHOICE VOLTAGE REFERENCE INPUT Internal Reference, REF = 4.096 V (PDREF Low) External 1.2 V Reference and Internal Buffer (PDREF High) External Reference (PDREF High, REFIN Low) Reference Decoupling POWER SUPPLY DIGITAL INTERFACE DATA READING OPTIONS Reading During Conversion, Fast Host (Turbo or Normal Mode) Split Reading, Any Speed Host (Turbo or Normal Mode) Reading During Acquisition, Any Speed Host (Turbo or Normal Mode) CS\ MODE, 3-WIRE WITHOUT BUSY INDICATOR CS\ MODE, 3-WIRE WITH BUSY INDICATOR CS\ MODE, 4-WIRE WITHOUT BUSY INDICATOR CS\ MODE, 4-WIRE WITH BUSY INDICATOR CHAIN MODE WITHOUT BUSY INDICATOR CHAIN MODE WITH BUSY INDICATOR APPLICATIONS INFORMATION LAYOUT EVALUATING AD7944 PERFORMANCE OUTLINE DIMENSIONS ORDERING GUIDE