SBOS872A May   2018  – June 2018 OPA521

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      OPA521 Block Diagram
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 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 Electrical Characteristics
    6. 6.6 Electrical Characteristics: Digital
    7. 6.7 Electrical Characteristics: Power Supply
    8. 6.8 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 IQSET Pin
      2. 7.3.2 EN Pin
      3. 7.3.3 ILIM Pin Current Limiting
      4. 7.3.4 IFLAG and TFLAG Pins
    4. 7.4 Device Functional Modes
  8. 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 Interfacing the OPA521 to the AC Mains
          1. 8.2.2.1.1 Low-Voltage Capacitor
          2. 8.2.2.1.2 High-Voltage Capacitor
          3. 8.2.2.1.3 Inductor
          4. 8.2.2.1.4 Line Coupling Transformer
        2. 8.2.2.2 Circuit Protection
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Thermal Considerations
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Community Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.2.2.1.2 High-Voltage Capacitor

The high-voltage capacitor (HV Cap) blocks the low-frequency mains voltage by forming a voltage divider with the winding inductance of the line coupling transformer. In many applications, a maximum reactive power (VA limit) on the HV Cap may be required. To meet this requirement, the HV Cap value is calculated by Equation 1.

Equation 1. OPA521 eq-01-sbos872.gif

For a 240-VAC, 50-Hz application with a 10-VA limit, the maximum value for the HV Cap is shown in Equation 2.

Equation 2. OPA521 eq-02-sbos872.gif

A 470-nF capacitor is frequently used in these types of applications. A metallized polypropylene electromagnetic interference and radio frequency interference (EMI/RFI) suppression capacitor is recommended because of the low loss factor associated with the dielectric, which results in minimal internal self-heating. Operating the capacitor at approximately 80% of its ac-rated voltage ensures a long component operating life. See Circuit Protection of this document for additional discussion on selecting the correct HV Cap value to withstand impulses on the mains.