SBAU269C October   2016  – August 2021 ADS8900B

 

  1.   Trademarks
  2. 1EVM Overview
    1. 1.1 ADS8900EVM-PDK Kit Features
    2. 1.2 ADS8900EVM Features
  3. 2Analog Interface
    1. 2.1 ADS8900B Connections and Decoupling
    2. 2.2 ADC Amplifier Input Drive
    3. 2.3 Voltage Reference and VCM Scaling
  4. 3Digital Interface
    1. 3.1 multiSPI™ for ADC Digital I/O
    2. 3.2 I2C Bus for Onboard EEPROM
  5. 4Power Supplies
    1. 4.1 Positive Supply and Test Points
    2. 4.2 Negative Supply
  6. 5ADS8900EVM-PDK Initial Setup
    1. 5.1 Software Installation
    2. 5.2 Default Jumper Settings for Differential Inputs
    3. 5.3 Default Jumpers for Bipolar, Single-Ended Inputs
    4. 5.4 Default Jumpers for Unipolar, Single-Ended Inputs
    5. 5.5 External Source Requirements for ADS8900 Evaluation
  7. 6ADS8900EVM-PDK Operation
    1. 6.1 EVM GUI Global Settings for ADC Control
    2. 6.2 Register Map Configuration Tool
    3. 6.3 Time Domain Display Tool
    4. 6.4 Spectral Analysis Tool
    5. 6.5 Histogram Tool
    6. 6.6 Linearity Analysis Tool
    7. 6.7 ADS8900BEVM Support for ADS8910B and ADS8920B Devices
  8. 7Bill of Materials, PCB Layout, and Schematics
    1. 7.1 Bill of Materials (BOM)
    2. 7.2 PCB Layout
    3. 7.3 Schematics
  9. 8Revision History

6.7 ADS8900BEVM Support for ADS8910B and ADS8920B Devices

This software also allows for the direct evaluation of the ADS8910B (18-bit) and ADS8920B (16-bit) devices by emulating their operation with the ADS8900B (20-bit) device. Update the EEPROM file for either the ADS8910B or the ADS8920B in order for the GUI to operate in these modes. First, install a jumper on JP5 so the EEPROM properly updates. If a jumper is not applied across JP5, an error message appears and the EEPROM does not load. Click on the Load EEPROM option in the Tools tab at the top of the GUI window and (as shown in Figure 6-10) a separate window appears, asking for a device to be selected. After loading the new EEPROM file, the ADS8910B or ADS8920B can now be evaluated using the ADS8900B.

Because the ADS8900B has a resolution of 20 bits, emulating a device with a lower resolution results in the software clocking out the number of bits of the device being emulated. For example, if the ADS8920B (which has a resolution of 16 bits) is being emulated, the software discards the last four LSBs and only clocks out 16 bits of data. When a device with a lower resolution is being emulated, the AC performance characteristics (such as SNR and THD) match the lower resolution devices.

Note:

When running an emulation for the ADS8910B or ADS8920B using an ADS8900B, source synchronous mode cannot be used. Source synchronous mode is enabled by setting SDO mode to multiSPI. If source synchronous mode is selected when emulating a device, an error occurs and the software enters a nonworking state. A power cycle and software reset is required to recover functionality.

Figure 6-10 Load EEPROM

For direct evaluation of the ADS8910B or ADS8920B, replace the ADS8900B with an ADS8910B or ADS8920B. After loading the correct EEPROM file, the EVM hardware and software properly communicates with the updated device. With a direct device replacement on the ADS8900BEVM, source synchronous mode can be used.