ZHCSKT4B february   2020  – december 2020 ISOW7841A-Q1

PRODUCTION DATA  

  1.   1
  2. 1 特性
  3. 2 应用
  4. 3 说明
  5. 4 Revision History
  6. 5 Description Continued
  7. 6 Pin Configuration and Functions
  8. 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—5-V Input, 5-V Output
    10. 7.10 Supply Current Characteristics—5-V Input, 5-V Output
    11. 7.11 Electrical Characteristics—3.3-V Input, 5-V Output
    12. 7.12 Supply Current Characteristics—3.3-V Input, 5-V Output
    13. 7.13 Electrical Characteristics—5-V Input, 3.3-V Output
    14. 7.14 Supply Current Characteristics—5-V Input, 3.3-V Output
    15. 7.15 Electrical Characteristics—3.3-V Input, 3.3-V Output
    16. 7.16 Supply Current Characteristics—3.3-V Input, 3.3-V Output
    17. 7.17 Switching Characteristics—5-V Input, 5-V Output
    18. 7.18 Switching Characteristics—3.3-V Input, 5-V Output
    19. 7.19 Switching Characteristics—5-V Input, 3.3-V Output
    20. 7.20 Switching Characteristics—3.3-V Input, 3.3-V Output
    21. 7.21 Insulation Characteristics Curves
    22. 7.22 Typical Characteristics
  9. 8 Parameter Measurement Information
  10. 9 Detailed Description
    1. 9.1 Overview
    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 Current Limit, Thermal Overload Protection
    4. 9.4 Device Functional Modes
      1. 9.4.1 Device I/O Schematics
  11. 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
        1. 10.2.3.1 Insulation Lifetime
  12.   Power Supply Recommendations
  13. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 PCB Material
    2. 11.2 Layout Example
  14. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Development Support
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Community Resources
    5. 12.5 Glossary
  15. 13Mechanical, Packaging, and Orderable Information

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9.1 Overview

The ISOW7841A-Q1 has a high-efficiency, low-emissions isolated DC-DC converter, and four high-speed isolated data channels. Block Diagram shows the functional block diagram of the ISOW7841A-Q1.

The integrated DC-DC converter uses switched mode operation and proprietary circuit techniques to reduce power losses and boost efficiency. Specialized control mechanisms, clocking schemes, and the use of a high-Q on-chip transformer provide high efficiency and low radiated emissions. The integrated transformer uses thin film polymer as the insulation barrier.

The VCC supply is provided to the primary power controller that switches the power stage connected to the integrated transformer. Power is transferred to the secondary side, rectified and regulated to either 3.3 V or 5 V, depending on the SEL pin. The output voltage, VISO, is monitored and feedback information is conveyed to the primary side through a dedicated isolation channel. The duty cycle of the primary switching stage is adjusted accordingly. The fast feedback control loop of the power converter ensures low overshoots and undershoots during load transients. Undervoltage lockout (UVLO) with hysteresis is integrated on the VCC and VISO supplies which ensures robust system performance under noisy conditions. An integrated soft-start mechanism ensures controlled inrush current and avoids any overshoot on the output during power up.

The integrated signal-isolation channels employ an ON-OFF keying (OOK) modulation scheme to transmit the digital data across a silicon-dioxide based isolation barrier. The transmitter sends a high-frequency carrier across the barrier to represent one state and sends no signal to represent the other state. The receiver demodulates the signal after signal conditioning and produces the output through a buffer stage. The signal-isolation channels incorporate advanced circuit techniques to maximize the CMTI performance and minimize the radiated emissions from the high frequency carrier and IO buffer switching. Figure 9-2 shows a functional block diagram of a typical signal isolation channel.

The ISOW7841A-Q1 is suitable for applications that have limited board space and require more integration. This device is also suitable for very-high voltage applications, where power transformers meeting the required isolation specifications are bulky and expensive.