SLLSFO4D December   2022  – August 2025 ISOM8710 , ISOM8711

PRODMIX  

  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  Power Ratings
    6. 6.6  Insulation Specifications
    7. 6.7  Safety-Related Certifications
    8. 6.8  Safety Limiting Values
    9. 6.9  Electrical Characteristics—DC 
    10. 6.10 Switching Characteristics, ISOM8710
    11. 6.11 Switching Characteristics, ISOM8711
    12. 6.12 Typical Characteristics
  8. 7 Parameter Measurement Information
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
    4. 8.4 Device Functional Modes
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Sizing RIN
        2. 9.2.2.2 Driving the Input with a Buffer
        3. 9.2.2.3 Calculating RL for ISOM8711
      3. 9.2.3 Application Curves
      4. 9.2.4 Insulation Lifetime
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Documentation Support
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Support Resources
    4. 10.4 Trademarks
    5. 10.5 Electrostatic Discharge Caution
    6. 10.6 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

9.2.2.1 Sizing RIN

The input side of ISOM871x is current-driven. To limit the amount of current flowing into the AN pin, use a series resistor, RIN, in series with the input as shown in Figure 9-1.

RIN can be sized to minimize current flow and power consumption through the ISOM871x input-side, or the resistor can be sized to enable higher data rates, depending on the application requirements. Regardless of the requirements, RIN must be a value that limits the input forward current to be within the Recommended Operating Conditions for ISOM871x. The equation to calculate RIN for a given input voltage, VIN, and desired input forward current, IF, is shown in Equation 1 where VF is the maximum spec for the ISOM871x input forward voltage:

Equation 1. RIN = VIN - VF MAXIF

For example, with a 24V input and 10mA desired IF, RIN can be calculated as:

Equation 2. RIN = 24 V - 1.8 V10 mA =2.22 kΩ