SBAS655F September   2014  – January 2020 AMC1304L05 , AMC1304L25 , AMC1304M05 , AMC1304M25


  1. Features
  2. Applications
  3. Description
    1.     Device Images
      1.      Simplified Schematic
  4. Revision History
  5. Device Comparison Table
  6. Pin Configuration and Functions
    1.     Pin Functions
  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: AMC1304x05
    10. 7.10 Electrical Characteristics: AMC1304x25
    11. 7.11 Switching Characteristics
    12. 7.12 Insulation Characteristics Curves
    13. 7.13 Typical Characteristics
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Analog Input
      2. 8.3.2 Modulator
      3. 8.3.3 Digital Output
    4. 8.4 Device Functional Modes
      1. 8.4.1 Fail-Safe Output
      2. 8.4.2 Output Behavior in Case of a Full-Scale Input
  9. Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Digital Filter Usage
    2. 9.2 Typical Applications
      1. 9.2.1 Frequency Inverter Application
        1. Design Requirements
        2. Detailed Design Procedure
        3. Application Curve
      2. 9.2.2 Isolated Voltage Sensing
        1. Design Requirements
        2. Detailed Design Procedure
        3. Application Curve
      3. 9.2.3 What To Do and What Not To Do
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Examples
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Device Nomenclature
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Related Links
    4. 12.4 Receiving Notification of Documentation Updates
    5. 12.5 Community Resources
    6. 12.6 Trademarks
    7. 12.7 Electrostatic Discharge Caution
    8. 12.8 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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


The modulator implemented in the AMC1304 is a second-order, switched-capacitor, feed-forward ΔΣ modulator, such as the one conceptualized in Figure 48. The analog input voltage VIN and the output V5 of the 1-bit digital-to-analog converter (DAC) are differentiated, providing an analog voltage V1 at the input of the first integrator stage. The output of the first integrator feeds the input of the second integrator stage, resulting in output voltage V3 that is differentiated 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 its analog output voltage V5, causing the integrators to progress in the opposite direction and forcing the value of the integrator output to track the average value of the input.

AMC1304L05 AMC1304L25 AMC1304M05 AMC1304M25 ai_modulator_bas654.gifFigure 48. Block Diagram of a Second-Order Modulator

The modulator shifts the quantization noise to high frequencies, as shown in Figure 49. Therefore, use a low-pass digital filter at the output of the device to increase the overall performance. This filter is also used to convert from the 1-bit data stream at a high sampling rate into a higher-bit data word at a lower rate (decimation). TI's microcontroller families TMS320F2807x and TMS320F2837x offer a suitable programmable, hardwired filter structure termed a sigma-delta filter module (SDFM) optimized for usage with the AMC1304 family. Also, SD24_B converters on the MSP430F677x microcontrollers offer a path to directly access the integrated sinc-filters, thus offering a system-level solution for multichannel, isolated current sensing. An additional option is to use a suitable application-specific device, such as the AMC1210 (a four-channel digital sinc-filter). Alternatively, a field-programmable gate array (FPGA) can be used to implement the digital filter.

AMC1304L05 AMC1304L25 AMC1304M05 AMC1304M25 ai_quant_noise_sbas655.gifFigure 49. Quantization Noise Shaping