SBAU411 February   2023 ADS127L21

 

  1.   Abstract
  2.   Trademarks
  3. 1EVM Overview
    1. 1.1 ADS127L21 EVM Kit
    2. 1.2 ADS127L21EVM Board
    3. 1.3 ADS127L21EVM-PDK-GUI Unsupported Features
    4. 1.4 Related Documentation
  4. 2Analog Interface
    1. 2.1 EVM Analog Input Options
    2. 2.2 ADC Connections and Decoupling
    3. 2.3 ADC Input Drive Amplifiers
    4. 2.4 VCOM Buffer
    5. 2.5 Onboard Voltage Reference
    6. 2.6 External Voltage Reference
    7. 2.7 Clock Tree
  5. 3Digital Interface
    1. 3.1 Serial Interface
    2. 3.2 I2C bus for Onboard EEPROM
  6. 4Power Supplies
    1. 4.1 Power Connection and Configuration
    2. 4.2 Low Dropout Regulator (LDO)
  7. 5ADS127L21 EVM Software Installation
  8. 6EVM Operation
    1. 6.1 Connecting the Hardware
    2. 6.2 Optional EVM Connections
    3. 6.3 EVM GUI Global Settings for ADC Control
    4. 6.4 Time Domain Display
    5. 6.5 Frequency Domain Display
    6. 6.6 Histogram Display
    7. 6.7 Digital Filter Configuration
    8. 6.8 Digital Filter Response
  9. 7Bill of Materials, Schematics, and Layout
    1. 7.1 Bill of Materials
    2. 7.2 Schematics
    3. 7.3 Board Layout

2.1 EVM Analog Input Options

For best performance, differential analog input signals can be connected through the SMA connectors (J3 and J6). Header J4 can also directly connect inputs for dc measurements, or where best ac performance is not needed. For single-ended inputs, header J4 can connect AINN or AINP to GND. Then use either J3 or J6 as the single-ended input. The input driver circuit uses the THS4561 fully-differential amplifier in a unity-gain, second-order, low-pass filter configuration with a single-pole RC filter at the output. Multiple passive components around the amplifier are intentionally left uninstalled to give users the flexibility to customize the input drive circuit for their specific application.

When differential inputs are connected to the SMA connectors (J3 and J6), make sure header J4 does not have any connection to pins 1 or 4.