SBASB14B October   2024  – October 2025 AMC0311S-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  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 (D Package)
    5. 6.5  Thermal Information (DWV Package)
    6. 6.6  Power Ratings 
    7. 6.7  Insulation Specifications (Basic Isolation)
    8. 6.8  Insulation Specifications (Reinforced Isolation)
    9. 6.9  Safety-Related Certifications (Basic Isolation)
    10. 6.10 Safety-Related Certifications (Reinforced Isolation)
    11. 6.11 Safety Limiting Values (D Package)
    12. 6.12 Safety Limiting Values (DWV Package)
    13. 6.13 Electrical Characteristics
    14. 6.14 Switching Characteristics
    15. 6.15 Timing Diagram
    16. 6.16 Insulation Characteristics Curves
    17. 6.17 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Analog Input
      2. 7.3.2 Isolation Channel Signal Transmission
      3. 7.3.3 Analog Output
      4. 7.3.4 Reference Input
    4. 7.4 Device Functional Modes
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Input Filter Design
        2. 8.2.2.2 Connecting the REFIN Pin
      3. 8.2.3 Application Curve
    3. 8.3 Best Design Practices
    4. 8.4 Power Supply Recommendations
    5. 8.5 Layout
      1. 8.5.1 Layout Guidelines
      2. 8.5.2 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

8.2.2 Detailed Design Procedure

The 200μA cross-current requirement at the maximum DC bus voltage (960V) determines that the total impedance of the resistive divider is 4.80MΩ. The impedance of the resistive divider is dominated by the top portion, shown exemplary as R1 and R2 in the Typical Application figure. The maximum allowed voltage drop per unit resistor is specified as 125V. Therefore, the minimum number of unit resistors in the top portion of the resistive divider is 960V / 125V ≅ 8. The calculated unit value is 4.80MΩ / 8 = 600kΩ and the next closest value from the E96 series is 604kΩ. Size RSNS such that the voltage drop across the resistor at the maximum DC bus voltage (960V) equals VFSR. VFSR is the linear full-scale voltage and is specified as 2.25V. RSNS is calculated as RSNS = VFSR / (VDC-link, MAX – VFSR) × RTOP. RTOP is the total value of the top resistor string (8 × 604kΩ = 4.832MΩ). RSNS results in a value of 11.35kΩ. The next closest value from the E96 series is 11.3kΩ.

Table 8-2 summarizes the design of the resistive divider.

Table 8-2 Resistor Value Examples
PARAMETER VALUE
Unit resistor value, RTOP 604kΩ
Number of unit resistors in RTOP 8
Sense resistor value, RSNS 11.3kΩ
Total resistance value (RTOP + RSNS) 4.843MΩ
Resulting current through resistive divider, ICROSS 198.2μA
Resulting full-scale voltage drop across sense resistor RSNS 2.24V
Peak power dissipated in RTOP unit resistor 23.7mW
Total peak power dissipated in resistive divider 190.3mW