SLLSFP4 July   2022 ISOW7721

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1  Absolute Maximum Ratings
    2. 7.2  ESD Ratings
    3. 7.3  Recommended Operating Conditions
    4. 7.4  Thermal Information
    5. 7.5  Power Ratings
    6. 7.6  Insulation Specifications
    7. 7.7  Safety-Related Certifications
    8. 7.8  Safety Limiting Values
    9. 7.9  Electrical Characteristics - Power Converter
    10. 7.10 Supply Current Characteristics - Power Converter
    11. 7.11 Electrical Characteristics Channel Isolator - VIO, VISOIN = 5-V
    12. 7.12 Supply Current Characteristics Channel Isolator - VIO, VISOIN = 5-V
    13. 7.13 Electrical Characteristics Channel Isolator - VIO, VISOIN = 3.3-V
    14. 7.14 Supply Current Characteristics Channel Isolator - VIO, VISOIN = 3.3-V
    15. 7.15 Electrical Characteristics Channel Isolator - VIO, VISOIN = 2.5-V
    16. 7.16 Supply Current Characteristics Channel Isolator - VIO, VISOIN = 2.5-V
    17. 7.17 Electrical Characteristics Channel Isolator - VIO, VISOIN = 1.8-V
    18. 7.18 Supply Current Characteristics Channel Isolator - VIO, VISOIN = 1.8-V
    19. 7.19 Switching Characteristics - 5-V Supply
    20. 7.20 Switching Characteristics - 3.3-V Supply
    21. 7.21 Switching Characteristics - 2.5-V Supply
    22. 7.22 Switching Characteristics - 1.8-V Supply
    23. 7.23 Insulation Characteristics Curves
    24. 7.24 Typical Characteristics
  8. 8 Parameter Measurement Information
  9. 9 Detailed Description
    1. 9.1 Overview
      1. 9.1.1 Power Isolation
      2. 9.1.2 Signal Isolation
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Electromagnetic Compatibility (EMC) Considerations
      2. 9.3.2 Power-Up and Power-Down Behavior
      3. 9.3.3 Protection Features
      4. 9.3.4 Multi-Device Chaining for Increased Power Output
    4. 9.4 Device Functional Modes
      1. 9.4.1 Device I/O Schematics
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
      3. 10.2.3 Application Curve
      4. 10.2.4 Insulation Lifetime
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
      1. 12.1.1 PCB Material
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Device Support
      1. 13.1.1 Development Support
    2. 13.2 Documentation Support
      1. 13.2.1 Related Documentation
    3. 13.3 Receiving Notification of Documentation Updates
    4. 13.4 Support Resources
    5. 13.5 Trademarks
    6. 13.6 Electrostatic Discharge Caution
    7. 13.7 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

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

12.1 Layout Guidelines

A low cost two layer PCB should be sufficient to achieve good EMC performance:

  • Routing the high-speed traces on the top layer avoids the use of vias (and the introduction of their inductances) and allows for clean interconnects between the isolator and the transmitter and receiver circuits of the data link.
  • Placing a solid ground plane next to the high-speed signal layer establishes controlled impedance for transmission line interconnects and provides an excellent low-inductance path for the return current flow.
  • Placing the power plane next to the ground plane creates additional high-frequency bypass capacitance of approximately 100 pF/in2.
  • Routing the slower speed control signals on the bottom layer allows for greater flexibility as these signal links usually have margin to tolerate discontinuities such as vias.
If an additional supply voltage plane or signal layer is needed, add a second power or ground plane system to the stack to keep it symmetrical. This makes the stack mechanically stable and prevents it from warping. Also the power and ground plane of each power system can be placed closer together, thus increasing the high-frequency bypass capacitance significantly.

Because the device has no thermal pad to dissipate heat, the device dissipates heat through the respective GND pins. Ensure that enough copper is present on both GND pins to prevent the internal junction temperature of the device from rising to unacceptable levels.

Figure 12-1 shows the recommended placement and routing of device bypass capacitors. Below guidelines must be followed to meet application EMC requirements:

  • High frequency bypass capacitors 10 nF must be placed close to VDD and VISOOUT pins, less than 1 mm distance away from device pins. This is very essential for optimised radiated emissions performance. Ensure that these capacitors are 0402 size so that they offer least inductance (ESL).
  • Bulk capacitors of atleast 10 μF must be placed on power converter input (VDD) and output (VISOOUT) supply pins.
  • Traces on VDD and GND1 must be symmetric till bypass capacitors. Similarly traces on VISOOUT and GND2 must be symmetric.
  • Place two 0402 size Ferrite beads (Part number: BLM15EX331SN1) on VISOOUT and GND2 path so that any high frequency noise from power converter output sees a high impedance before it goes to other components on PCB.
  • Do not have any metal traces or ground pour within 4 mm of power converter output terminals VISOOUT pin12 and GND2 pin11. VSEL pin is also in VISOOUT domain and should be shorted to either pin 11 or pin 12 for output voltage selection.
  • Following the layout guidelines of EVM as much as possible is highly recommended for a low radiated emissions design.