AD7949 Analog Devices, AD7949 Datasheet - Page 2

• Manufacturer Part Number: AD7949
• Description: 14-Bit, 8-Channel, 250 kSPS PulSAR ADC
• Manufacturer: Analog Devices

Specifications of AD7949

• Resolution (bits): 14bit
• # Chan: 8
• Sample Rate: 250kSPS
• Interface: Ser,SPI
• Analog Input Type: Diff-Uni,SE-Uni
• Adc Architecture: SAR
• Pkg Type: CSP

AD7949
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications....................................................................................... 1
Functional Block Diagram .............................................................. 1
General Description ......................................................................... 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
Absolute Maximum Ratings............................................................ 7
Pin Configuration and Function Descriptions............................. 8
Typical Performance Characteristics ............................................. 9
Terminology .................................................................................... 12
Theory of Operation ...................................................................... 13
REVISION HISTORY
8/11—Rev. B to Rev. C
Changes to Internal Reference Section........................................ 18
Changes to External Reference and Internal Buffer Section and
External Reference Section............................................................ 19
Changes to Bits[5:3] Function, Table 9........................................ 22
5/09—Rev. A to Rev. B
Changes to Features Section, Applications Section, and
Figure 1 .............................................................................................. 1
Changes to Specifications Section.................................................. 3
Changes to Timing Specifications Section.................................... 5
Changes to Table 5............................................................................ 7
Changes to Figure 4 and Table 6..................................................... 8
Changes to Figure 20...................................................................... 11
Changes to Converter Operation Section ................................... 13
Changes to Table 7.......................................................................... 14
Changes to Figure 25 and Figure 26............................................. 15
Changes to Bipolar Single Supply Section, Input Structure
Section, and Selectable Low-Pass Filter Section......................... 16
Changes to Input Configurations Section, Sequencer Section,
and Source Resistance Section...................................................... 17
Changes to Internal Reference/Temperature Sensor Section ... 18
Added Figure 30; Renumbered Sequentially .............................. 18
Changes to External Reference and Internal Buffer Section,
External Reference Section, and Reference Decoupling
Section.............................................................................................. 19
Timing Specifications .................................................................. 5
ESD Caution.................................................................................. 7
Overview...................................................................................... 13
Converter Operation.................................................................. 13
Transfer Functions...................................................................... 14
Typical Connection Diagrams.................................................. 15
Analog Inputs.............................................................................. 16
Driver Amplifier Choice............................................................ 18
Rev. C | Page 2 of 32
Digital Interface .............................................................................. 21
Application Hints ........................................................................... 28
Outline Dimensions ....................................................................... 29
Added Figure 31 and Figure 32 .................................................... 19
Changes to Power Supply Section ................................................ 20
Changed Reading/Writing During Conversion, Fast Hosts
Section to Reading/Writing After Conversion,
Any Speed Hosts............................................................................. 21
Changes to Configuration Register, CFG Section and
Table 9 .............................................................................................. 22
Added General Timing Without a Busy Indicator Section and
Figure 36 .......................................................................................... 23
Added General Timing with a Busy Indicator Section and
Figure 37 .......................................................................................... 24
Added Channel Sequencer Section, Examples Section, and
Figure 38 .......................................................................................... 25
Changes to Read/Write Spanning Conversion Without a Busy
Indicator Section and Figure 40 ................................................... 26
Changes to Read/Write Spanning Conversion with a Busy
Indicator Section and Figure 42 ................................................... 27
Changes to Evaluating AD7949 Performance Section .............. 28
Added Exposed Pad Notation to Outline Dimensions ............. 29
Changes to Ordering Guide .......................................................... 29
5/08—Rev. 0 to Rev. A
Changes to Ordering Guide .......................................................... 26
5/08—Revision 0: Initial Version
Voltage Reference Output/Input .............................................. 18
Power Supply............................................................................... 20
Supplying the ADC from the Reference.................................. 20
Reading/Writing During Conversion, Fast Hosts.................. 21
Reading/Writing After Conversion, Any Speed Hosts.......... 21
Reading/Writing Spanning Conversion, Any Speed Host.... 21
Configuration Register, CFG .................................................... 21
General Timing Without a Busy Indicator ............................. 23
General Timing with a Busy Indicator .................................... 24
Channel Sequencer .................................................................... 25
Read/Write Spanning Conversion Without a Busy Indicator
....................................................................................................... 26
Read/Write Spanning Conversion with a Busy Indicator..... 27
Layout .......................................................................................... 28
Evaluating AD7949 Performance............................................. 28
Ordering Guide .......................................................................... 29
Data Sheet