SLVAF40 July   2021 TPS2661

 

  1.   Trademarks
  2. 1Introduction
  3. 2Discrete Solution With PTC
  4. 3TPS26610 Advantages to a Typical Solution
    1. 3.1 BOM and Size Reduction
    2. 3.2 Burden Resistor and Power Dissipation
    3. 3.3 Voltage Drop
    4. 3.4 Signal Good
    5. 3.5 Additional TPS26610 Features
      1. 3.5.1 Miswiring
      2. 3.5.2 Surge
      3. 3.5.3 Current-Loop Test During Installation (Unpowered)
      4. 3.5.4 High Accuracy For Current Measurements
  5. 4Conclusion

1 Introduction

In industrial applications, the equipment must operate reliably in harsh environments. In an analog IO module, input power and analog signal protections are needed to operate in harsh environments, fulfilling various standards. Field transmitters set the current loop based on the value of physical quantities such as temperature and pressure. The set current is then converted into voltage using a burden resistor inside the analog input module. The goal of the design is to ensure that the precision burden resistor and the analog-to-digital converter (ADC) front end are well protected.

Focusing on analog signal protections, it is important to be compliant with mandatory standards to protect the module from surges (IEC61000-4-5) and electrical fast transients (EFT). It is also necessary to consider and manage accidental events such as mis-wiring during installation and wire-short, the unwanted connection between two cables which causes a short circuit during operations that can occur in a factory.