TIDUF19 September   2022 ADS1282-SP

 

  1.   Description
  2.   Resources
  3.   Features
  4.   Applications
  5.   5
  6. 1System Description
  7. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 Rset, Rref, and Gain Calculation
      2. 2.2.2 Analog Multiplexer Effect
    3. 2.3 Highlighted Products
      1. 2.3.1 ADS1282-SP
      2. 2.3.2 LMP7704-SP
      3. 2.3.3 TPS7A4501-SP
      4.      16
  8. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware Requirements
    2. 3.2 Software Requirements
    3. 3.3 Test Setup
    4. 3.4 Test Results
  9. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 BOM
    2. 4.2 Documentation Support
    3. 4.3 Support Resources
    4. 4.4 Trademarks
  10. 5About the Author

2.1 Block Diagram

This reference design uses equivalent commercial components on the PCB instead of the full space grade ICs for electrical performance evaluation. Compare to space grade IC, commercial devices have similar electrical characteristics but is not radiation tolerant. In addition, ADS1282-SP is not placed on TIDA-060042. Instead, TIDA-060042 is designed to connect to ADS1282EVM-PDK for temperature measurement. Figure 2-1 illustrates the recommended comprehensive block diagram, and Figure 2-2 illustrates how TIDA-060042, the RTD board, is connects to ADS1282EVM-PDK for temperature measurement.

Figure 2-1 Temperature Sensing Application Block Diagram

LMP7704-SP, a rail-to-rail input and output op-amp, supplies a fixed current to each of the RTDs as well as to Rset and Rref. The value of Rset will set the current drawn by the series resistances, thus to adjust the current, Rset needs to be modified. The bias voltage is set to 0.75 V. Voltage across Rref is the ADS1282-SP reference voltage for setting the ADC Full Scale Range (FSR). Compared to Figure 2-1, Figure 2-2 has the mux removed. Only RTD1 and RTD10 are connected to ADS1282EVM-PDK for evaluating the effect of common mode voltage (Vcm) on the measured result.

Figure 2-2 Connection Between TIDA-060042 and ADS1282EVM-PDK