SBAS928C February   2020  – September 2023 ADS7066

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Timing Requirements
    7. 6.7 Switching Characteristics
    8. 6.8 Timing Diagrams
    9. 6.9 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Analog Input and Multiplexer
      2. 7.3.2  Reference
        1. 7.3.2.1 External Reference
        2. 7.3.2.2 Internal Reference
      3. 7.3.3  ADC Transfer Function
      4. 7.3.4  ADC Offset Calibration
      5. 7.3.5  Programmable Averaging Filters
      6. 7.3.6  CRC on Data Interface
      7. 7.3.7  Oscillator and Timing Control
      8. 7.3.8  Diagnostic Modes
        1. 7.3.8.1 Bit-Walk Test Mode
        2. 7.3.8.2 Fixed Voltage Test Mode
      9. 7.3.9  Output Data Format
        1. 7.3.9.1 Status Flags
        2. 7.3.9.2 Output CRC (Device to Host)
        3. 7.3.9.3 Input CRC (Host to Device)
      10. 7.3.10 Device Programming
        1. 7.3.10.1 Enhanced-SPI Interface
        2. 7.3.10.2 Daisy-Chain Mode
        3. 7.3.10.3 Register Read/Write Operation
          1. 7.3.10.3.1 Register Write
          2. 7.3.10.3.2 Register Read
            1. 7.3.10.3.2.1 Register Read With CRC
    4. 7.4 Device Functional Modes
      1. 7.4.1 Device Power-Up and Reset
      2. 7.4.2 Manual Mode
      3. 7.4.3 On-the-Fly Mode
      4. 7.4.4 Auto-Sequence Mode
    5. 7.5 ADS7066 Registers
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Charge-Kickback Filter and ADC Amplifier
      3. 8.2.3 Application Curve
    3. 8.3 Power Supply Recommendations
      1. 8.3.1 AVDD and DVDD 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 Device Support
      1. 9.1.1 Development Support
    2. 9.2 Documentation Support
      1. 9.2.1 Related Documentation
    3. 9.3 Receiving Notification of Documentation Updates
    4. 9.4 Support Resources
    5. 9.5 Trademarks
    6. 9.6 Electrostatic Discharge Caution
    7. 9.7 Glossary
  11. 10Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.8.1 Bit-Walk Test Mode

To enable write access to the configuration registers for diagnostics, write 0x96 in the DIAGNOSTICS_KEY register. To enable bit-walk test mode, configure BITWALK_EN = 1b. In the bit-walk test mode (see Figure 7-1), the sampling switch (SW) remains open and the test voltage is applied on the sampling capacitor (CSH) during the acquisition phase of the ADC. In diagnostic mode, the conversion process of the ADC remains the same as normal device operation. The ADC starts the conversion phase on the rising edge of CS and outputs the code corresponding to the sampled test voltage. The output code of the ADC is expected to be proportional to the test voltage, as shown in Equation 2, after adjusting for DC errors (such as INL, gain error, offset error, and thermal drift of offset and gain errors).

Equation 2. GUID-DB6AC2AF-AA90-4BD1-9F6E-E4D2FCC1C602-low.gif

where

  • TUE = Total unadjusted error, given by the root sum square of the offset error, gain error, and INL

The test voltage is generated by a DAC configured by the BIT_SAMPLE_MSB and BIT_SAMPLE_LSB registers. Because the test voltage is derived from the ADC reference, as given by Equation 3, this diagnostic mode is not sensitive to variations in reference voltage.

Equation 3. GUID-9D427395-16A7-422C-85C3-08983F370255-low.gif

To resume conversion of the ADC input signal, configure BITWALK_EN = 0b.