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

5.4.1 ADC1 Analog Inputs

The SNSR-DUAL-ADC-EVM default settings configure ADC1 to measure the output signals of a resistive bridge. However, the user can configure the channels to measure general purpose sensor signals. Figure 5-4 shows the analog input filtering and additional circuitry connected to ADC1.

AIN2 and AIN3 form a differential pair that measures the input signals between SIGNAL+ and SIGNAL-. The default EVM settings configure AIN4 and AIN5 as the reference between SENSE+ and SENSE-. The user can also configure AIN4 and AIN5 as a differential pair to measure input signals. The default EVM settings configure AIN1 as the excitation source return path from an external bridge circuit. However, AIN1 can also be used as a single-ended measurement input when resistor R12 is removed.

ADC1 supports resistive bridge, thermocouple, 3- and 4-wire resistance temperature detectors (RTDs), and generic voltage and current input measurements. See Analog Sensor Connections for additional details regarding how to connect sensors to the SNSR-DUAL-ADC-EVM board.

ADS122S14EVM ADC1 Analog Front End Figure 5-4 ADC1 Analog Front End

The ADC1 analog inputs include first-order resistor-capacitor filters that limit aliasing and noise effects. The differential pairs include an additional common-mode capacitor that filters common-mode noise. Equation 3 shows the calculation for the differential cut-off frequency. Equation 4 shows the calculation for the common-mode cut-off frequency.

Equation 1. fcdiff = 1/[2π × (R1 + R2) × Cdiff] = 1/ [2π × (1000 + 1000) × 0.01μF] ≅ 8kHz
Equation 2. fccm = 1/[2π × R × Ccm] = 1/ [2π × 1000 × 1000pF] ≅ 160kHz