SBASA74B January   2023  – May 2024 ADS9218 , ADS9219

PRODMIX  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1  Absolute Maximum Ratings
    2. 5.2  ESD Ratings
    3. 5.3  Thermal Information
    4. 5.4  Recommended Operating Conditions
    5. 5.5  Electrical Characteristics
    6. 5.6  Timing Requirements
    7. 5.7  Switching Characteristics
    8. 5.8  Timing Diagrams
    9. 5.9  Typical Characteristics: All Devices
    10. 5.10 Typical Characteristics: ADS9219
    11. 5.11 Typical Characteristics: ADS9218
    12. 5.12 Typical Characteristics: ADS9217
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Analog Inputs
      2. 6.3.2 Analog Input Bandwidth
      3. 6.3.3 ADC Transfer Function
      4. 6.3.4 Reference Voltage
      5. 6.3.5 Temperature Sensor
      6. 6.3.6 Data Averaging
      7. 6.3.7 Digital Down Converter
      8. 6.3.8 Data Interface
        1. 6.3.8.1 Data Frame Width
        2. 6.3.8.2 Synchronizing Multiple ADCs
        3. 6.3.8.3 Test Patterns for Data Interface
          1. 6.3.8.3.1 Fixed Pattern
          2. 6.3.8.3.2 Alternating Test Pattern
          3. 6.3.8.3.3 Digital Ramp
      9. 6.3.9 ADC Sampling Clock Input
    4. 6.4 Device Functional Modes
      1. 6.4.1 Reset
      2. 6.4.2 Power-Down Options
      3. 6.4.3 Normal Operation
      4. 6.4.4 Initialization Sequence
    5. 6.5 Programming
      1. 6.5.1 Register Write
      2. 6.5.2 Register Read
      3. 6.5.3 Multiple Devices: Daisy-Chain Topology for SPI Configuration
        1. 6.5.3.1 Register Write With Daisy-Chain
        2. 6.5.3.2 Register Read With Daisy-Chain
  8. 7 Register Map
    1. 7.1 Register Bank 0
    2. 7.2 Register Bank 1
    3. 7.3 Register Bank 2
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Data Acquisition (DAQ) Circuit for ≤20kHz Input Signal Bandwidth
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Data Acquisition (DAQ) Circuit for ≤100kHz Input Signal Bandwidth
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Application Curves
      3. 8.2.3 Data Acquisition (DAQ) Circuit for ≤1MHz Input Signal Bandwidth
        1. 8.2.3.1 Design Requirements
        2. 8.2.3.2 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information
    1. 11.1 Mechanical Data

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

6.3.3 ADC Transfer Function

The ADS921x supports a ±3.2V differential input range. The device outputs 18-bit conversion data in either straight-binary or binary two's-complement formats. As shown in Table 6-1, the format for the output codes is the same across all analog channels. Configure the format for the output codes with the DATA_FORMAT field in register address 0x0D. The least significant bit (LSB) for the ADC is given by 1LSB = 6.4V / 218.

Table 6-1 Transfer Characteristics
INPUT VOLTAGE DESCRIPTION ADC OUTPUT IN 2's-COMPLEMENT FORMAT ADC OUTPUT IN STRAIGHT-BINARY FORMAT
≤ –3.2V + 1LSB Negative full-scale code 0x80000 0x00000
0V + 1LSB Mid-code 0x00000 0x1FFFF
≥ 3.2V – 1LSB Positive full-scale code 0x1FFFF 0x3FFFF