TIDUEU6B September   2020  – December 2021 OPA810

 

  1.   Description
  2.   Resources
  3.   Features
  4.   Applications
  5.   5
  6. 1System Description
    1. 1.1 Key System Specifications
  7. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Highlighted Products
      1. 2.2.1 OPA2810
      2. 2.2.2 BUF634A
    3. 2.3 Design Considerations
      1. 2.3.1 Existing architecture
        1. 2.3.1.1 Circuit Stability Issue
        2. 2.3.1.2 Solution in Existing Architecture (Compensation Cap)
      2. 2.3.2 Proposed Design
        1. 2.3.2.1 Stability Analysis of the Proposed Design
          1. 2.3.2.1.1 Without Measurement of Voltage at Inverting Node of A2
          2. 2.3.2.1.2 With Measuring Voltage at Inverting Node of A2
        2. 2.3.2.2 RG = RF Settings and Respective Impedance Ranges
        3. 2.3.2.3 Impedance Measurement Procedure
          1. 2.3.2.3.1 Short Cal
          2. 2.3.2.3.2 Impedance Cal
          3. 2.3.2.3.3 100k Setting Calibration
          4. 2.3.2.3.4 Open Cal
          5. 2.3.2.3.5 Calculations
          6. 2.3.2.3.6 Correction in ZX
          7. 2.3.2.3.7 Data Acquisition and Processing
          8. 2.3.2.3.8 Mathematical Explanation
  8. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Required Hardware and Software
      1. 3.1.1 Hardware
    2. 3.2 Testing and Results
      1. 3.2.1 Test Setup
      2. 3.2.2 Test Results
  9. 4Design Files
    1. 4.1 Schematics
    2. 4.2 Bill of Materials
    3. 4.3 PCB Layout Recommendations
      1. 4.3.1 Layout Prints
    4. 4.4 Altium Project
    5. 4.5 Gerber Files
    6. 4.6 Assembly Drawings
  10. 5Software Files
  11. 6Related Documentation
    1. 6.1 Trademarks
    2. 6.2 Third-Party Products Disclaimer
  12. 7Revision History

2.3.2 Proposed Design

GUID-D9982D7E-F410-4EE5-8C4F-EBD482547A12-low.gifFigure 2-6 Impedance Measurement Design

In this method, three different combinations of RG – RF (labeled as R1, R2 & R3 in Figure 2-6) are selected for three ranges of impedance ZX. The ranges can be seen in Table 2-1. The architecture in this method is very similar to the existing architecture explained in last section. The only difference is that the RG is added in series with ZX. Also the value of RG is equal to RF. The stability analysis in Section 2.3.2.1 explains the advantage of this kind of setting.