SNIS245B September   2025  – July 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 Mechanical Data
    2. 11.2 Package Option Addendum
    3. 11.3 Tape and Reel Information

8.1.2 Output Buffering and Signal Integrity Considerations

In many applications, the ISOTMP35R-Q1 output can be connected directly to an ADC input without requiring an external buffer. The output stage provides sufficient drive capability for typical capacitive loads and short PCB interconnects.

As described in Section 7.3.2.2, the output remains stable for capacitive loads up to 2.2nF without additional components. For larger capacitive loads, the use of a series isolation resistor (RISO) enables stable operation independent of load capacitance. In these cases, an external buffer is not required for stability.

In certain system conditions, an external buffer can improve overall signal integrity and robustness. These conditions are typically related to long PCB traces, cable interfaces, multiple loads, or electrically noisy environments where signal attenuation and coupling can degrade performance.

An external buffer can be implemented as either a single-ended or differential stage, depending on system requirements. Single-ended buffers are typically sufficient for moderate trace lengths and low-noise environments. Differential signaling can be used in applications requiring improved noise immunity or reliable transmission over longer distances.

In addition, buffering can help isolate the sensor output from downstream circuitry, reducing the impact of distributed parasitics and improving performance in high-EMI environments.

Figure 8-1 shows an example implementation in which the ISOTMP35R-Q1 output is buffered and transmitted as a differential signal for improved noise immunity over longer distances.

ISOTMP35R-Q1 Buffered Differential Pair Data TransmissionFigure 8-1 Buffered Differential Pair Data Transmission

In applications with short trace lengths, a single load, and limited noise coupling, the ISOTMP35R-Q1 output can be used directly without a buffer.