SBASB01 August   2024 AMC3306M05-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1  Absolute Maximum Ratings
    2. 5.2  ESD Ratings
    3. 5.3  Recommended Operating Conditions
    4. 5.4  Thermal Information
    5. 5.5  Power Ratings
    6. 5.6  Insulation Specifications
    7. 5.7  Safety-Related Certifications 
    8. 5.8  Safety Limiting Values
    9. 5.9  Electrical Characteristics
    10. 5.10 Switching Characteristics
    11. 5.11 Timing Diagrams
    12. 5.12 Insulation Characteristics Curves
    13. 5.13 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Analog Input
      2. 6.3.2 Modulator
      3. 6.3.3 Isolation Channel Signal Transmission
      4. 6.3.4 Digital Output
        1. 6.3.4.1 Output Behavior in Case of a Full-Scale Input
        2. 6.3.4.2 Output Behavior in Case of a High-Side Supply Failure
      5. 6.3.5 Isolated DC/DC Converter
      6. 6.3.6 Diagnostic Output
    4. 6.4 Device Functional Modes
  8. 7 Application and Implementation
    1. 7.1 Application Information
      1. 7.1.1 Digital Filter Usage
    2. 7.2 Typical Application
      1. 7.2.1 Onboard Charger (OBC) Application
        1. 7.2.1.1 Design Requirements
        2. 7.2.1.2 Detailed Design Procedure
          1. 7.2.1.2.1 Shunt Resistor Sizing
          2. 7.2.1.2.2 Input Filter Design
          3. 7.2.1.2.3 Bitstream Filtering
        3. 7.2.1.3 Application Curve
      2. 7.2.2 Best Design Practices
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Documentation Support
      1. 8.1.1 Related Documentation
    2. 8.2 Receiving Notification of Documentation Updates
    3. 8.3 Support Resources
    4. 8.4 Trademarks
    5. 8.5 Electrostatic Discharge Caution
    6. 8.6 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

6.3.2 Modulator

Figure 6-2 conceptualizes the second-order, switched-capacitor, feed-forward ΔΣ modulator implemented in the AMC3306M05-Q1. The output V5 of the 1-bit, digital-to-analog converter (DAC) is subtracted from the input voltage VIN = (VINN – VINP) and results in a voltage V1. V1 feeds the input of the first integrator stage. The output of the first integrator feeds the input of the second integrator stage, resulting in an output voltage V3. V3 is summed with the input signal VIN and the output of the first integrator V2. Depending on the polarity of the resulting voltage V4, the output of the comparator is changed. In this case, the 1-bit DAC responds on the next clock pulse by changing the associated analog output voltage V5. This change causes the integrators to progress in the opposite direction and forces the value of the integrator output to track the average input value.

AMC3306M05-Q1 Block Diagram of a Second-Order Modulator Figure 6-2 Block Diagram of a Second-Order Modulator

The modulator shifts the quantization noise to high frequencies, as illustrated in Figure 6-1. Therefore, use a low-pass digital filter, such as a SINC filter, at the output of the device to increase signal to noise ratio. This filter also converts the 1-bit data stream at a high sampling rate into a higher-bit data word at a lower rate (decimation). TI's C2000™ and Sitara™ microcontroller families offer a suitable programmable, hardwired filter structure termed a sigma-delta filter module (SDFM) optimized for usage with the AMC3306M05-Q1. Alternatively, use a field-programmable gate array (FPGA) or complex programmable logic device (CPLD) to implement the filter.