SBAU448 September   2024 ADS8681W

 

  1.   1
  2.   Description
  3.   Get Started
  4.   Features
  5.   Applications
  6.   6
  7. 1Evaluation Module Overview
    1. 1.1 Introduction
    2. 1.2 Performance Development Kit Contents
    3. 1.3 Specification
    4. 1.4 Device Information
  8. 2Hardware
    1. 2.1 EVM Analog Interface
      1. 2.1.1 ADC Analog Input Signal Path
      2. 2.1.2 Onboard ADC Reference
    2. 2.2 Power Supplies
  9. 3Software
    1. 3.1 Digital Interfaces
      1. 3.1.1 multiSPITM SPI for ADC Digital IO
    2. 3.2 ADS8681WEVM-PDK Initial Setup
      1. 3.2.1 Default Jumper and Switch Settings
      2. 3.2.2 EVM Graphical User Interface (GUI) Software Installation
  10. 4Implementation Results
    1. 4.1 ADS8681WEVM-PDK Operation
      1. 4.1.1 EVM GUI Global Settings for ADC control
      2. 4.1.2 Register Map Configuration Tool
      3. 4.1.3 Time Domain Display Tool
      4. 4.1.4 Histogram Tool
      5. 4.1.5 Spectral Analysis Tool
      6. 4.1.6 Linearity Analysis Tool
  11. 5Hardware Design Files
    1. 5.1 ADS8681WEVM-PDK Schematic
    2. 5.2 PCB Layout
    3. 5.3 Bill of Materials
  12. 6Additional Information
    1. 6.1 Trademarks
  13. 7Related Documentation

2.2 Power Supplies

The PHI provides multiple power supply options for the ADS8681WEVM, derived from the USB supply of the computer. The EEPROM on the ADS8681WEVM uses a common 3.3V power supply (EVM_ID_PWR) generated directly by the PHI. The ADC and analog input drive circuits are powered by the TPS7A4901 onboard the EVM. The TPS7A4901 is a low-noise linear regulator that uses the 5.5V supply out of a switching regulator on the PHI to generate a much cleaner 5V output (AVDD) for all analog circuits on the EVM board. The LDO circuit that generates AVDD is shown in Figure 2-4.

ADS8681WEVM-PDK Analog Supply Circuit Figure 2-4 Analog Supply Circuit

The analog supply can be also provided by an external power supply when a jumper is installed on pin 2-3 position of J4. The 3.3V power supply to the digital section of the ADC is provided directly by an LDO on the PHI (EVM_DVDD).