AD7785 Analog Devices, AD7785 Datasheet - Page 2

• Manufacturer Part Number: AD7785
• Description: 3-Channel, Low Noise, Low Power, 20-Bit ?-? ADC with On-Chip In-Amp and Reference
• Manufacturer: Analog Devices

Specifications of AD7785

• Resolution (bits): 20bit
• # Chan: 3
• Sample Rate: n/a
• Interface: Ser,SPI
• Analog Input Type: Diff-Uni
• Ain Range: ± (Vref/Gain)
• Adc Architecture: Sigma-Delta
• Pkg Type: SOP

AD7785
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications....................................................................................... 1
General Description ......................................................................... 1
Functional Block Diagram .............................................................. 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
Timing Characteristics..................................................................... 6
Absolute Maximum Ratings............................................................ 8
Pin Configuration and Function Descriptions............................. 9
Output Noise and Resolution Specifications .............................. 11
Typical Performance Characteristics ........................................... 13
On-Chip Registers .......................................................................... 14
REVISION HISTORY
4/07—Revision 0: Initial Version
Timing Diagrams.......................................................................... 7
ESD Caution.................................................................................. 8
External Reference...................................................................... 11
Internal Reference ...................................................................... 12
Communications Register......................................................... 14
Status Register ............................................................................. 15
Mode Register ............................................................................. 15
Configuration Register .............................................................. 17
Data Register ............................................................................... 18
ID Register................................................................................... 18
IO Register................................................................................... 18
Rev. 0 | Page 2 of 32
ADC Circuit Information.............................................................. 20
Circuit Description......................................................................... 25
Applications Information .............................................................. 29
Outline Dimensions ....................................................................... 31
Offset Register ............................................................................ 19
Full-Scale Register...................................................................... 19
Overview ..................................................................................... 20
Digital Interface.......................................................................... 21
Analog Input Channel ............................................................... 25
Instrumentation Amplifier........................................................ 25
Bipolar/Unipolar Configuration .............................................. 25
Data Output Coding .................................................................. 25
Burnout Currents ....................................................................... 26
Excitation Currents .................................................................... 26
Bias Voltage Generator .............................................................. 26
Reference ..................................................................................... 26
Reset ............................................................................................. 26
AV
Calibration................................................................................... 27
Grounding and Layout .............................................................. 27
Temperature Measurement using a Thermocouple............... 29
Temperature Measurement using an RTD.............................. 30
Ordering Guide .......................................................................... 31
DD
Monitor ............................................................................. 27