SNVAA98 January   2024 LM25148 , LM74910-Q1 , TPS38700 , TPS389006 , TPS389006-Q1 , TPS628301 , TPS628302 , TPS628303 , TPS6287B10 , TPS6287B15 , TPS6287B20 , TPS6287B25 , TPS746

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1 Introduction
  5. 2 Design Parameters
  6. 3 Schematics
  7. 4 Design Considerations
  8. 5 Front-End Protection
  9. 6 3.3V Always-ON Bias Supply
  10. 7 5V Pre-Regulator Buck Converter
  11. 8 Low-Voltage High-Current Core Rail Buck Converter
  12. 9 On-Board Core Rail Output Load Transient Stepper
  13. 10Multiple Peripheral Rail Buck Converters Sub-Circuits Schematic
  14. 11Voltage Supervisor and Sequencer
  15. 1212-Channel Sequencer Alternative
  16. 13Summary
  17. 14References

6 3.3V Always-ON Bias Supply

A simple wide input voltage LDO is used to provide an always-ON 3.3V bias supply. This is used mainly to power the on-board voltage supervisor and sequencer ICs, as well as make available a positive supply for high level pull-up or enable signals. If the system already has a voltage rail that is independent of the rails in this application brief, with a value of 3.3V or similar low voltage that can be used to supply the voltage supervisor and sequencer ICs, then this LDO is no longer necessary.