SBOA626 December   2025 OPA187 , OPA192 , OPA202 , OPA320

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 Simple Analogy Explaining Instability
    2. 1.2 Circuits With Possible Stability Issues
    3. 1.3 Simple Stability Correction Based on Datasheet Plots
    4. 1.4 Introducing Lab Tools and Measurements
  5. 2Stability Theory for Operational Amplifiers
    1. 2.1 Poles and Zeros
    2. 2.2 Operational Amplifier Model Requirements for Stability Verification
    3. 2.3 Stability Definitions Based on Control Loop Model
    4. 2.4 Graphing Loop-Gain Based on AOL and 1/β
    5. 2.5 Rate of Closure Stability Test
    6. 2.6 Indirect (Non-Invasive) Stability Tests
  6. 3Simulating Open-Loop Stability Tests
    1. 3.1 Breaking the Loop the Wrong Way
    2. 3.2 Breaking the Loop With LC Test Circuit
    3. 3.3 Differential Loop Break Test
  7. 4Stability Correction for Capacitive Load
    1. 4.1 Isolation Resistor (RISO) Method
    2. 4.2 Dual Feedback Method
      1. 4.2.1 RISO-Dual-Feedback With RL
      2. 4.2.2 Dual Feedback With RFX Method
    3. 4.3 Snubber Circuit for Compensating Power Amplifiers and Reference Drive
    4. 4.4 Noise Gain for Stability Compensation
    5. 4.5 Feedback Capacitor (CF) Compensation for Capacitive Load
  8. 5Stability Corrections for Capacitance on the Inverting Node
    1. 5.1 Input Capacitance Instability Due to Zero in 1/β
    2. 5.2 Feedback Capacitor Solves Stability Issue for Capacitance on the Inverting Node
    3. 5.3 Minimum, Balanced, and Maximum Feedback Capacitance
    4. 5.4 Transimpedance Case
  9. 6Complex Open-Loop and Closed-Loop Output Impedance
    1. 6.1 Converting Open-Loop Output Impedance to Closed-Loop Output Impedance
    2. 6.2 Open-Loop and Closed-Loop Model Test
    3. 6.3 Instability Due to Resonance From Complex Output Impedance
    4. 6.4 Impact of Internal Op Amp Topology on Output Impedance Versus Frequency
    5. 6.5 Other Factors Effecting Output Impedance
  10. 7AOL Impact on Stability
    1. 7.1 AOL Secondary Poles and Zeros
    2. 7.2 Modeling the AOL Secondary Poles and Zeros and Input Capacitance
    3. 7.3 Decompensated Op Amps and Stability
    4. 7.4 The Impact of Closed-Loop Gain on Stability
  11. 8Common Problems in Stability Analysis
  12. 9References

Trademarks

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