SLVAG05 October   2025 TPS7A56 , TPS7A57 , TPS7A94 , TPS7A96

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction to LDO Noise and Noise Measurement
    1. 1.1 LDO Noise and LDO Noise Representation
    2. 1.2 Measuring LDO Noise Using a Spectrum Analyzer
  5. 2Solution for Measuring an Ultra-Low Noise LDO (Noise Amplifier Requirements)
    1. 2.1 Estimating the Maximum Noise for the Amplifier
    2. 2.2 Estimating the Amplifier Needed Gain
    3. 2.3 Selecting the Amplifier Circuit Feedback Resistor Values
    4. 2.4 The Amplifier Input/Output DC Blocking Filters
    5. 2.5 Verifying the Designed Amplifier Performance
  6. 3Conclusion
  7. 4References

Abstract

This technical white paper provides an outline for measuring noise for a low dropout regulator (LDO). This document also provides a solution for measuring noise for ultra-low noise LDOs. Current LDOs can have output noise levels substantially below the sensitivity for the vast spectrum analyzers available on the market. This document discusses the noise measurement basics of LDOs and options for measuring extremely, low-noise LDOs. The proposed solution is not solely limited to noise measurements intended for LDOs, the option can be used in many other types of measurement or sensing applications.