SBAU378A September   2021  – January 2022 ADS1148 , ADS1248

 

  1.   Trademarks
  2. 1Introduction
  3. 2Getting Started With the ADS1x48EVM
  4. 3ADS1x48EVM Overview
    1. 3.1 Analog and Digital Power Supplies
    2. 3.2 Voltage Reference Options
    3. 3.3 Clock Options
    4. 3.4 Digital Interface
    5. 3.5 Analog Input Connections
      1. 3.5.1 Connecting a Thermocouple to J5 on the ADS1x48EVM
      2. 3.5.2 Connecting a Thermistor to J5 on the ADS1x48EVM
        1. 3.5.2.1 Using Thermistor RT1 for Thermocouple Cold Junction Compensation
      3. 3.5.3 Connecting an RTD to J6 on the ADS1x48EVM
        1. 3.5.3.1 Connecting a 2-Wire RTD Using a Low-Side RREF to J6 on the ADS1x48EVM
        2. 3.5.3.2 Connecting a 2-Wire RTD Using a High-Side RREF to J6 on the ADS1x48EVM
        3. 3.5.3.3 Connecting a 3-Wire RTD Using One IDAC and a Low-Side RREF to J6 on the ADS1x48EVM
        4. 3.5.3.4 Connecting a 3-Wire RTD Using One IDAC and a High-Side RREF to J6 on the ADS1x48EVM
        5. 3.5.3.5 Connecting a 3-Wire RTD Using Two IDACs and a Low-Side RREF to J6 on the ADS1x48EVM
        6. 3.5.3.6 Connecting a 3-Wire RTD Using Two IDACs and a High-Side RREF to J6 on the ADS1x48EVM
        7. 3.5.3.7 Connecting a 4-Wire RTD Using a Low-Side RREF to J6 on the ADS1x48EVM
        8. 3.5.3.8 Connecting a 4-Wire RTD Using a High-Side RREF to J6 on the ADS1x48EVM
        9. 3.5.3.9 Summary of ADS1x48EVM RTD Configuration Settings
      4. 3.5.4 Connecting a General-Purpose Input to J5 on the ADS1x48EVM
  5. 4ADS1x48EVM GUI
    1. 4.1 Home
      1. 4.1.1 Menu Bar
        1. 4.1.1.1 File Menu
        2. 4.1.1.2 Options Menu
        3. 4.1.1.3 Tools Menu
        4. 4.1.1.4 Help Menu
    2. 4.2 Data Capture
      1. 4.2.1 Time Domain and Histogram Statistics
      2. 4.2.2 Time Domain Plot
      3. 4.2.3 Histogram Plot
      4. 4.2.4 FFT Statistics and Plot
    3. 4.3 Register Map
      1. 4.3.1 Register Read and Write Options
        1. 4.3.1.1 Read Register Options
        2. 4.3.1.2 Write Register Options
  6. 5Bill of Materials, Printed Circuit Board Layout, and Schematic
    1. 5.1 Bill of Materials
    2. 5.2 Printed Circuit Board Layout
    3. 5.3 Schematic
  7. 6Revision History

3.5 Analog Input Connections

The ADS1x48EVM is designed for easy interface to external temperature sensors using the two screw terminal blocks (J5 and J6). Connector J5 provides connections for thermocouples and thermistors as well as the 2.048-V output voltage from the ADS1x48 integrated reference and the dedicated 2.5-V output from the REF5025. Connector J6 includes a pair of differential reference inputs for connecting an external voltage reference source to the ADC as well as three dedicated terminals for connecting a 2-, 3-, or 4-wire RTD. Table 3-3 summarizes the channel input connections for J5 and J6. Both connectors are clearly labeled on the PCB silkscreen for easy input connection identification. Figure 3-6 shows the input layout.

Table 3-3 ADS1x48EVM Terminal Block Input Description (J5 and J6)
Terminal Block InputLabelDescription
J5:1TC+Positive thermocouple, general-purpose input
J5:2TC–Negative thermocouple, general-purpose input
J5:3REF50252.5-V output from REF5025
J5:4REFOUT2.048-V output from ADS1x48 integrated VREF
J5:5NTC+Positive thermistor input
J5:6NTC–Negative thermistor input
J6:1REFP1Positive external VREF input to ADC
J6:2REFN1Negative external VREF input to ADC
J6:3RTD_ARTD connection point A
J6:4RTD_BRTD connection point B
J6:5RTD_CRTD connection point C
J6:6GNDAnalog ground
GUID-20210706-CA0I-DVLC-1P6M-Z3WRLCGV1QRT-low.pngFigure 3-6 ADS1x48EVM Analog Input Terminal Blocks (J5, Left; J6, Right)

The following sections describe how to connect each different analog temperature sensor to its respective connector, beginning with terminal block J5.