SBAU431A July   2024  – October 2026

 

  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 Input Options
    2. 2.2  Common-Mode Amplifier
    3. 2.3  Analog Input Circuit
    4. 2.4  RTD Current Source
    5. 2.5  Voltage Reference
    6. 2.6  ADC Connections and Decoupling
    7. 2.7  Power Supplies
    8. 2.8  SYNC / Clock Divide Circuit
    9. 2.9  Clocking
    10. 2.10 Serial Interface
    11. 2.11 EEPROM
    12. 2.12 Using the ADS1282EVM With an External Controller
  9. 3Software
    1. 3.1 Software Description
    2. 3.2 ADS1282 EVM Software Installation
  10. 4Implementation Results
    1. 4.1 EVM Operation
      1. 4.1.1 Evaluation Setup
      2. 4.1.2 EVM Register Settings
        1. 4.1.2.1 Channel Configuration
        2. 4.1.2.2 PGA Gain Selection
        3. 4.1.2.3 Data Rate Configuration
      3. 4.1.3 Time Domain Display
      4. 4.1.4 Spectral Analysis Display
      5. 4.1.5 Histogram Analysis Display
      6. 4.1.6 GUI Data Export
  11. 5Hardware Design Files
    1. 5.1 Schematics
    2. 5.2 PCB Layouts
    3. 5.3 Bill of Materials (BOM)
  12. 6Additional Information
    1. 6.1 Trademarks
  13. 7Related Documentation
    1. 7.1 Supplemental Content
  14. 8Revision History

2.4 RTD Current Source

Figure 2-4 shows a constant 1mA current source that can be used for biasing resistance temperature detectors (RTDs) in precision temperature measurement applications. This current source is realized using amplifier U5, an OPA196 precision amplifier. Precision resistor R45 establishes a 1V reference input to the ADS1282 and sets the current level. Increase the value of resistor R45 if the system requires a lower RTD current bias. For example, changing R45 from 1kΩ to 10kΩ sets the bias current to 100µA.

The current source output is available on terminal block J6 or header JP8. Connect one or two RTDs in series from terminal block J6 pin 1 (F2+) to terminal block J6 pin 3 (F1-). Terminal block J6 pin 2 (F2-, F1+) is included as a convenient point to connect two RTDs in series, as shown in Figure 2-5.

ADS1282EVM-PDK RTD Current SourceFigure 2-4 RTD Current Source
ADS1282EVM-PDK External RTD ConnectionsFigure 2-5 External RTD Connections