SBAS654G June   2014  – January 2020 AMC1305L25 , AMC1305M05 , AMC1305M25

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin 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: AMC1305M05
    10. 7.10 Electrical Characteristics: AMC1305x25
    11. 7.11 Switching Characteristics
    12. 7.12 Insulation Characteristics Curves
    13. 7.13 Typical Characteristics
  8. 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 Full-Scale Input
  9. 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. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Application Curve
      2. 9.2.2 Isolated Voltage Sensing
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 Application Curve
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Examples
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Related Links
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Support Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

8.3.1 Analog Input

The AMC1305 incorporates front-end circuitry that contains a differential amplifier and sampling stage, followed by a ΔΣ modulator. The gain of the differential amplifier is set by internal precision resistors to a factor of 4 for devices with a specified input voltage range of ±250 mV (for the AMC1305x25), or to a factor of 20 for devices with a ±50-mV input voltage range (for the AMC1305M05), resulting in a differential input impedance of 5 kΩ (for the AMC1305M05) or 25 kΩ (for the AMC1305x25).

Consider the input impedance of the AMC1305 in designs with high-impedance signal sources that can cause degradation of gain and offset specifications. The importance of this effect, however, depends on the desired system performance. Additionally, the input bias current caused by the internal common-mode voltage at the output of the differential amplifier causes an offset that depends on the actual amplitude of the input signal. See the Isolated Voltage Sensing section for more details on reducing these effects.

There are two restrictions on the analog input signals (AINP and AINN). First, if the input voltage exceeds the range of AGND – 6 V to AVDD + 0.5 V, the input current must be limited to 10 mA because the device input electrostatic discharge (ESD) protection diodes turn on. In addition, 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 (FSR), that is ±250 mV (for the AMC1305x25) or ±50 mV (for the AMC1305M05), and within the specified input common-mode range.