SLAAED5B June   2023  – May 2026 AFE11612-SEP , INA951-SEP , OPA4H199-SEP

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1 LDMOS and GaN Power Amplifier FET PA Basics
  5. 2 VGS Compensation
  6. 3 Sequencing
  7. 4 An Integrated PA Biasing Solution
  8. 5 Negative Biasing for GaN PAs
  9. 6 Fast Switching for TDD Applications
  10. 7 VDRAIN Switching Circuit
  11. 8 Controlled Gate-Sequencing Circuit
  12. 9 VDRAIN Monitoring
  13. 10IDQ Monitoring
  14. 11External Negative Power Supply Monitoring
  15. 12PA Temperature Monitoring
  16. 13Summary
  17. 14References
  18. 15Revision History

11 External Negative Power Supply Monitoring

GaN PAs can be damaged if the VGS potential is too high, resulting in PA saturation. If the VSS supply collapses the differential op-amp output will slew to 0V. Thus, it is critical to monitor the VSS supply for collapse events. Monitoring can be done using a simple resistor divider biased by an external reference voltage, such as the 5V used for the device analog supply. A zener diode can be added for additional protection in case of the external 5V supply collapsing.

VSS Monitor Circuit Figure 11-1 VSS Monitor Circuit