SLUP409B April   2022  – April 2024 TPS543320 , TPS543620 , TPS543820 , TPS62913 , TPS62916

 

  1.   1
  2.   Abstract
  3. 1 Introduction
  4. 2 DC/DC Converters are Noisy
  5. 3 Power-Supply Output Voltage Ripple and Noise Degrade ADC Performance
  6. 4 Minimizing Low-Frequency Noise Requires Dedicated Low-Noise IC Technologies
  7. 5 Traditional Approaches to Reducing Ripple
  8. 6 Using Smaller Capacitors in Parallel
  9. 7 Larger Inductance
  10. 8 Adding a Feedthrough Capacitor
  11. 9 Adding a Ferrite Bead
  12. 10Layout Techniques
  13. 11Silicon Solutions
  14. 12Conclusions

12 Conclusions

This paper explored how to power noise-sensitive systems without LDO post-filtering, resulting in reduced power dissipation and system cooling costs. The total solution size decreases, and with a derived target for output voltage ripple and noise, it is possible to power high-speed, noise-sensitive systems for telecommunication and test-and-measurement applications.

It is also possible to optimize a DC/DC converter LC filter to lower the output voltage ripple in several ways. But only integrated low-noise circuit techniques can achieve truly low-frequency noise (<100kHz) on the output voltage of a DC/DC converter. A ferrite bead provides the most effective and affordable way to filter high-frequency noise >10MHz.

Both the TPS62913 and the TPS62916 addresses aspects of DC/DC fSW, low-noise and high-frequency filtering. This buck converter can power noise-sensitive loads without the need for LDO post-filtering, providing a tested and specified solution for today’s precision systems.