SBOA602 November   2024 OPA593

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Current Booster, Push-Pull Topology Output Characteristics
    1. 2.1 Open-Loop Output Impedance
    2. 2.2 Minimizing Zero Crossover Distortion
  6. 3Various Current Booster Configurations
    1. 3.1 Complementary MOSFET versus BJT Current Booster Comparisons
  7. 4Stabilizing a Design for Power Amplifier Driving 1μF Capacitive Load (CL)
    1. 4.1 Op-Amp Driving Resistive Load
    2. 4.2 Op-Amp Driving Capacitive Load and Challenges
    3. 4.3 Open-Loop AC Stability Analysis - Compensating CL Effects Using DFC
    4. 4.4 Closed-Loop Stability Response - Small Signal Step Transient Analysis
    5. 4.5 Effects of Riso on Frequency Response in Dual Feedback Compensation
    6. 4.6 Summary of the DFC Technique
  8. 5Stabilizing the OPA593 and Darlington Current Booster for 1μF Capacitive Load
    1. 5.1 Open-Loop AC Stability Analysis - Composite Op-Amp Driving 1μF CL
    2. 5.2 Closed-Loop Stability Response - Composite Op-Amp's Step Transient Analysis
  9. 6Composite Amplifier's Effective BW and Step Time Response
  10. 7Test Bench Validation
  11. 8Summary
  12. 9References

2 Current Booster, Push-Pull Topology Output Characteristics

The current booster’s open-loop output impedance and frequency response are among the key parameters in selecting a driver for ATE applications. The following criteria are summarized.

Table 2-1 Current Booster Driver Selection Criteria
NoCurrent Booster Driver Selection Guide
1Low and consistent open-loop output impedance, with Zo variation over frequency in a given application.
2Low distortion and high slew rate: Minimize crossover distortion while optimizing voltage biasing.
3Meet source or sink current requirements for driving large capacitive and resistive loads.
4Capability to withstand high power dissipation and effectively manage thermal stress under worst-case conditions.
5Maximizing output voltage swing headroom relative to programmable power supply voltage rails.
6Inclusion of output overvoltage and overcurrent protection features: overload, short-circuit, and current limiting.

Line items 1 through 3 in Table 2-2 regarding the current booster are addressed in Sections 2 and 3 of the article.