Datasheet AD7949 (Analog Devices) - 2

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AD7949 Data Sheet TABLE OF CONTENTS
Features .. 1 Voltage Reference Output/Input .. 19 Applications ... 1 Power Supply ... 21 Functional Block Diagram .. 1 Supplying the ADC from the Reference .. 21 General Description ... 1 Digital Interface .. 22 Revision History ... 3 Reading/Writing During Conversion, Fast Hosts .. 22 Specifications ... 4 Reading/Writing After Conversion, Any Speed Hosts .. 22 Timing Specifications .. 6 Reading/Writing Spanning Conversion, Any Speed Host .. 23 Absolute Maximum Ratings .. 8 Configuration Register, CFG .. 23 ESD Caution .. 8 General Timing Without a Busy Indicator ... 25 Pin Configuration and Function Descriptions ... 9 General Timing with a Busy Indicator .. 26 Typical Performance Characteristics ... 10 Channel Sequencer .. 27 Terminology .. 13 Read/Write Spanning Conversion Without a Busy Indicator Theory of Operation .. 14 ... 28 Overview .. 14 Read/Write Spanning Conversion with a Busy Indicator ... 30 Converter Operation .. 14 Application Hints ... 31 Transfer Functions.. 15 Layout .. 31 Typical Connection Diagrams .. 16 Evaluating AD7949 Performance ... 31 Analog Inputs .. 17 Outline Dimensions ... 32 Driver Amplifier Choice .. 19 Ordering Guide .. 32 Rev. F | Page 2 of 32 Document Outline FEATURES APPLICATIONS FUNCTIONAL BLOCK DIAGRAM GENERAL DESCRIPTION REVISION HISTORY SPECIFICATIONS TIMING SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS TERMINOLOGY THEORY OF OPERATION OVERVIEW CONVERTER OPERATION TRANSFER FUNCTIONS TYPICAL CONNECTION DIAGRAMS Unipolar or Bipolar Bipolar Single Supply ANALOG INPUTS Input Structure Selectable Low-Pass Filter Input Configurations Sequencer Source Resistance DRIVER AMPLIFIER CHOICE VOLTAGE REFERENCE OUTPUT/INPUT Internal Reference/Temperature Sensor External Reference and Internal Buffer External Reference Reference Decoupling POWER SUPPLY SUPPLYING THE ADC FROM THE REFERENCE DIGITAL INTERFACE READING/WRITING DURING CONVERSION, FAST HOSTS READING/WRITING AFTER CONVERSION, ANY SPEED HOSTS READING/WRITING SPANNING CONVERSION, ANY SPEED HOST CONFIGURATION REGISTER, CFG GENERAL TIMING WITHOUT A BUSY INDICATOR GENERAL TIMING WITH A BUSY INDICATOR CHANNEL SEQUENCER Examples READ/WRITE SPANNING CONVERSION WITHOUT A BUSY INDICATOR READ/WRITE SPANNING CONVERSION WITH A BUSY INDICATOR APPLICATION HINTS LAYOUT EVALUATING AD7949 PERFORMANCE OUTLINE DIMENSIONS ORDERING GUIDE