SNIS245A September   2025  – April 2026 ISOTMP35R-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1  Absolute Maximum Ratings
    2. 6.2  ESD Ratings
    3. 6.3  Recommended Operating Conditions
    4. 6.4  Thermal Information
    5. 6.5  Insulation Specification
    6. 6.6  Power Ratings
    7. 6.7  Safety-Related Certifications
    8. 6.8  Safety Limiting Values
    9. 6.9  Electrical Characteristics
    10. 6.10 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Functional Description
      1. 7.3.1 Integrated Isolation Barrier
      2. 7.3.2 Output Stage and Signal Behavior
        1. 7.3.2.1 Transfer Function
        2. 7.3.2.2 Driving Capacitive Loads
        3. 7.3.2.3 Common Mode Transient Immunity (CMTI)
      3. 7.3.3 Thermal Response
        1. 7.3.3.1 Stirred Liquid Thermal Response
        2. 7.3.3.2 Directional Thermal Response
          1. 7.3.3.2.1 Comparison to NTC Thermistors
        3. 7.3.3.3 Still Air Thermal Response
    4. 7.4 Device Functional Modes
  9. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Improving Accuracy Using Piecewise Linear Approximation
      2. 8.1.2 Output Buffering and Signal Integrity Considerations
      3. 8.1.3 ADC Interface Considerations
      4. 8.1.4 Power Supply Recommendations
      5. 8.1.5 EMI Mitigation and Filtering
        1. 8.1.5.1 Filtering Techniques
        2. 8.1.5.2 Design Guidelines for EMI Filtering
      6. 8.1.6 Insulation Lifetime
    2. 8.2 Layout
      1. 8.2.1 Layout Guidelines
      2. 8.2.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information
    1. 11.1 Package Option Addendum
    2. 11.2 Tape and Reel Information
    3. 11.3 Mechanical Data

8.1.5.2 Design Guidelines for EMI Filtering

The filtering configuration shown in Figure 8-3 illustrates a scalable approach that can be adapted based on system noise conditions and routing requirements. At a minimum, a capacitor (CLOAD) can be placed at the VOUT pin to provide local high-frequency filtering. Because this capacitor directly loads the output stage, the capacitor value must be selected in accordance with the capacitive-load drive capability described in Section 7.3.2.2. In applications without a series isolation resistor, the total effective capacitance seen at VOUT must not exceed 2.2nF.

A series isolation resistor (RISO), shown in Figure 8-3, is recommended for applications with downstream filtering, long trace lengths, or unknown capacitive loading. When RISO is greater than or equal to 300Ω, the output maintains a phase margin of at least 45° across the full capacitive-load range, allowing greater flexibility in downstream filtering.

An RC filter placed near the ADC input, consisting of RFLT_2 and CFLT_2, is recommended to attenuate high-frequency noise and to isolate the sensor output from ADC sampling transients. This stage represents the primary signal-conditioning filter for most applications.

Additional filtering stages, such as CFLT_1 and RFLT_1, can be used to further attenuate noise in systems with long routing distances or elevated electromagnetic interference. These stages are applied only as needed, based on system-level evaluation. Optional ferrite beads can be inserted in the signal path or supply path to suppress high-frequency interference. RFLT_3 is only required when the optional ferrite bead is populated, where it provides damping between the ferrite bead and downstream capacitance to suppress resonance and maintain stable filter behavior.

On the supply path, a local bypass capacitor (CBYPASS) must always be placed close to the VDD pin. Additional filtering using a ferrite bead and capacitor (CFLT_3) can be used to reduce conducted noise on the supply line. Only the capacitance directly connected to VOUT contributes to the effective load seen by the output stage. Capacitance located downstream of RISO does not affect output stability.

The component values used in Figure 8-3 provide a recommended starting point; however, the final values depend on system-level conditions, including noise spectrum, ADC characteristics, and PCB layout, and must be validated during system design.