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

2.3.2.2 RG = RF Settings and Respective Impedance Ranges

Table 2-1 explains the ranges for different components with respect to the RG - RF and frequency settings.

Table 2-1 Board Setting for Respective Impedance Range
PARAMETERSRG = RF SETTING
Frequency (Hz)Component100 Ω5 kΩ100 kΩ
100R1 Ω to 900 Ω500 Ω to 50 kΩ10 kΩ to 10 MΩ
L1.59 mH to 2.38 H2.27 H to 79.5 H72.9 H to 1432 H
C1.05 µF to 1.59 mF31.78 nF to 1.11 µF1.76 nF to 34.7 nF
1 kR1 Ω to 900 Ω500 Ω to 50 kΩ10 kΩ to 10 MΩ
L159 µH to 238 mH227 mH to 7.95 H7.29 H to 143.23 H
C106 nF to 159 µF3.178 nF to 111 nF176 pF to 3.47 nF
10 kR1 Ω to 900 Ω500 Ω to 50 kΩ10 kΩ to 10 MΩ
L25.9 µH to 23.8 mH22.6 mH to 795 mH729 mH to 14.3 H
C10.6 nF to 15.9 µF317.8 pF to 11.1 nF17.6 pF to 347 pF
100 kR1 Ω to 900 Ω500 Ω to 50 kΩ10 kΩ to 10 MΩ
L2.59 µH to 2.38 mH2.26 mH to 79.6 mH72 mH to 1.43 H
C1.06 nF to 1.59 µF31.78 pF to 1.11 nF1.76 pF to 34.7 pF

In the 100 kΩ setting, the parasitic cap at the inverting pin can make the circuit unstable. To overcome this problem a 5 pF capacitor is added in parallel with RF = 100 kΩ.