SBASAS5 October   2025 AMC0100R

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 (DEN Package)
    5. 5.5 Package Characteristics
    6. 5.6 Electrical Characteristics
    7. 5.7 Switching Characteristics
    8. 5.8 Timing Diagram
    9. 5.9 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 Isolation Channel Signal Transmission
      3. 6.3.3 Analog Output
    4. 6.4 Device Functional Modes
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 Shunt Resistor Sizing
        2. 7.2.2.2 Input Filter Design
        3. 7.2.2.3 Designing the Bootstrap Supply
        4. 7.2.2.4 Connecting the REFIN Pin
      3. 7.2.3 Application Curves
    3. 7.3 Best Design Practices
    4. 7.4 Power Supply Recommendations
    5. 7.5 Layout
      1. 7.5.1 Layout Guidelines
      2. 7.5.2 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

7.2.2.2 Input Filter Design

Place a differential RC filter (R1, R2, C5) in front of the isolated amplifier to improve signal-to-noise performance of the signal path. Design the input filter such that:

  • The cutoff frequency of the filter is at least one order of magnitude lower than the sampling frequency (20MHz) of the ΔΣ modulator
  • The input bias current does not generate significant voltage drop across the DC impedance of the input filter
  • The impedances measured from the analog inputs are equal

Place capacitors C6 and C7 to improve common-mode rejection at high frequencies (>1MHz) and to improve offset voltage performance. For best performance, verify C6 matches the value of C7 and that both capacitors are 10 to 20 times lower in value than C5. NP0-type capacitors offer low temperature drift and low voltage coefficients, and are preferred for common-mode filtering.

For most applications, the structure shown in Figure 7-2 achieves excellent performance.

AMC0100R Input Filter Figure 7-2 Input Filter