SLLSFS9D September   2023  – December 2024 ISOM8110 , ISOM8111 , ISOM8112 , ISOM8113 , ISOM8115 , ISOM8116 , ISOM8117 , ISOM8118

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 Thermal Information
    4. 6.4 Insulation Specifications
    5. 6.5 Safety-Related Certifications
    6. 6.6 Safety Limiting Values
    7. 6.7 Electrical Characteristics
    8. 6.8 Switching Characteristics
    9. 6.9 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
      1. 9.1.1 Typical Application
        1. 9.1.1.1 Design Requirements
        2. 9.1.1.2 Detailed Design Procedure
          1. 9.1.1.2.1 Sizing RPULLUP
          2. 9.1.1.2.2 Sizing RIN
        3. 9.1.1.3 Application Curves
    2. 9.2 Power Supply Recommendations
    3. 9.3 Layout
      1. 9.3.1 Layout Guidelines
      2. 9.3.2 Layout Example
      3. 9.3.3 Reflow Profile
  11. 10Device and Documentation Support
    1. 10.1 Documentation Support
      1. 10.1.1 Related Documentation
    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
9.1.1.2.1 Sizing RPULLUP

The transistor output of ISOM811x operates in active, saturation, reverse, and cut-off regions, just like a regular transistor. To verify that the output does not get damaged when the output is saturated, the minimum value of RPULLUP can be calculated for a given pull-up voltage, VPULLUP, in Equation 1:

Equation 1. R P U L L U P >   V P U L L U P -   V C E ( S A T ) I C ( M A X )

For the example of a feedback loop application, we can calculate the minimum required value for RPULLUP for a given VPULLUP of 10V, the maximum output voltage of the error amplifier (VCOMP(MAX) of 2.5V, and the maximum output current of the error amplifier is internally clamped at 1.6mA. The equation to calculate RPULLUP is shown in Equation 2:

Equation 2. R P U L L U P >   V P U L L U P -   V C O M P ( M A X ) I C O M P ( C L A M P ) =   10 V   -   2.5 V 1.6 m A =   4.66 k Ω