SBASA70 April   2021 AMC3336

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and 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  Power Ratings
    6. 6.6  Insulation Specifications
    7. 6.7  Safety-Related Certifications
    8. 6.8  Safety Limiting Values
    9. 6.9  Electrical Characteristics
    10. 6.10 Switching Characteristics
    11. 6.11 Timing Diagrams
    12. 6.12 Insulation Characteristics Curves
    13. 6.13 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 Analog Input
      2. 7.3.2 Modulator
      3. 7.3.3 Isolation Channel Signal Transmission
      4. 7.3.4 Digital Output
        1. 7.3.4.1 Output Behavior in Case of a Full-Scale Input
        2. 7.3.4.2 Output Behavior in Case of a High-Side Supply Failure
      5. 7.3.5 Isolated DC/DC Converter
      6. 7.3.6 Diagnostic Output
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Digital Filter Usage
    3. 8.3 Typical Application
      1. 8.3.1 Solar Inverter Application
        1. 8.3.1.1 Design Requirements
        2. 8.3.1.2 Detailed Design Procedure
          1. 8.3.1.2.1 Input Filter Design
          2. 8.3.1.2.2 Bitstream Filtering
        3. 8.3.1.3 Application Curve
    4. 8.4 What To Do and What Not To Do
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Device Nomenclature
        1. 11.1.1.1 Isolation Glossary
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Support Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary

7.3.1 Analog Input

The high-impedance input stage of the AMC3336 feeds a second-order, switched-capacitor, feed-forward ΔΣ modulator. The modulator converts the analog signal into a bitstream that is transferred over the isolation barrier, as described in the Section 7.3.3 section. The high-impedance, and low bias-current input makes the AMC3336 suitable for isolated, high-voltage-sensing applications that typically employ high impedance resistor dividers.

For reduced offset and offset drift, the input buffer is chopper-stabilized with the chopping frequency set at fCLKIN / 32. Figure 7-1 shows the spur at 625 kHz that is generated by the chopping frequency for a modulator clock of 20 MHz.

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sinc3 filter, OSR = 1, fCLKIN = 20 MHz, fIN = 1 kHz
Figure 7-1 Quantization Noise Shaping

There are two restrictions on the analog input signals (INP and INN). First, if the input voltage exceeds the input range specified in the Section 6.1 table, the input current must be limited to 10 mA because the device input electrostatic discharge (ESD) diodes turn on. Second, the linearity and noise performance of the device are ensured only when the differential analog input voltage remains within the specified linear full-scale range VFSR and within the specified input common-mode voltage range VCM as specified in the Section 6.3 table.