SLVUDH7 December   2025

 

  1.   1
  2. 1Description
  3. 2Features
  4. 3Applications
  5.   5
  6. 4Evaluation Module Overview
    1. 4.1 Introduction
    2. 4.2 Kit Contents
    3. 4.3 SNSR-DUAL-ADC-EVM Specifications
    4. 4.4 Device Information
    5. 4.5 Getting Started With the SNSR-DUAL-ADC-EVM
  7. 5Hardware
    1. 5.1  Hardware Overview
    2. 5.2  Power Requirements
    3. 5.3  ADC Connections and Decoupling
    4. 5.4  Analog Inputs
      1. 5.4.1 ADC1 Analog Inputs
      2. 5.4.2 ADC2 Analog Inputs
    5. 5.5  Excitation Connections and Low Side Bridge Switch
    6. 5.6  Analog Sensor Connections
      1. 5.6.1 Pressure Sensor (Resistive Bridge) Application Examples
        1. 5.6.1.1 Measuring a Voltage-Excited 6-wire Bridge Using ADC1 and a Low-side Bias Resistor Using ADC2
        2. 5.6.1.2 Measuring a Voltage-Excited 6-wire Bridge Using ADC1 and a Current-Excited 2-wire RTD Using ADC2
        3. 5.6.1.3 Measuring a Current-Excited 4-wire Bridge Using ADC1 and a Voltage-Excited Thermistor Using ADC2
      2. 5.6.2 Temperature Sensor Application Examples
        1. 5.6.2.1 Measuring a Thermocouple Using ADC1 and an NTC for Cold-Junction-Compensation Using ADC2
        2. 5.6.2.2 Measuring One 3-wire RTD Using ADC1 and One 3-wire RTD Using ADC2
        3. 5.6.2.3 Measuring One 4-wire RTD Using ADC1 and One 4-wire RTD Using ADC2
      3. 5.6.3 General Purpose Application Examples
        1. 5.6.3.1 Measuring Generic Voltage or Current Inputs
    7. 5.7  MSPM0G1507
    8. 5.8  Digital Interfaces
    9. 5.9  Digital Connection Headers
    10. 5.10 Shift Register
    11. 5.11 Connecting External Output Boards to Header J2
  8. 6Software
    1. 6.1 Top Level Menu
      1. 6.1.1 Top-level Help Menu Terminal
    2. 6.2 System Sub Menu
      1. 6.2.1 SYS Help Menu Output
    3. 6.3 ADC Sub Menu
      1. 6.3.1 ADC Help Menu Output
      2. 6.3.2 adc help Menu Input and Output Examples
        1. 6.3.2.1 adc reset Example
        2. 6.3.2.2 adc wreg Daisy-Chain Example (Writing to a Single ADC )
        3. 6.3.2.3 adc wreg Daisy-Chain Example (Writing to Both ADCs)
        4. 6.3.2.4 adc rreg Daisy-Chain Example
        5. 6.3.2.5 adc stream Example
        6. 6.3.2.6 adc lowpwr Example
  9. 7Hardware Design Files
    1. 7.1 Schematics
    2. 7.2 PCB Layout
    3. 7.3 Bill of Materials
  10. 8Compliance Information
  11. 9References

5.5 Excitation Connections and Low Side Bridge Switch

Figure 5-6 shows the sensor excitation circuitry. Header J4 functions as both an output and an input to the EVM. This header supports multiple sensor excitation sources, including VDD, REFOUT_ADC1, and IDAC_ADC1. EXC- completes the bridge connection to ground through the TMUX1219, which acts as a low-side bridge switch. The MSPM0G1507 controls the low-side bridge switch to either provide the bridge excitation with a path to ground or disconnect the bridge for power savings. Refer to Section 6.3.2.6 for additional information regarding how to operate the low side bridge switch.

In a current excitation bridge circuit, replace the 0Ω resistor R12 with a bias resistor to establish a valid common mode voltage for the bridge output. Additionally, this bias resistor provides a return path for the excitation current source.

ADS122S14EVM Excitation Header and Low Side Bridge Switch Figure 5-6 Excitation Header and Low Side Bridge Switch