SDAA203 November   2025 AFE7920

 

  1.   1
  2.   Abstract
  3. 1Introduction
  4. 2Issue Phenomenon and Observations
  5. 3Introduction to Phase Locked Loop (PLL)
  6. 4Design
  7. 5Summary
  8. 6References

4 Design

Graph Illustrating A Fix Figure 4-1 Graph Illustrating A Fix

Vctrl of measured value from the customer is therefore marginally close to a higher limit, resulting in a momentary PLL unlock. A better margin on at hot temperature is required. Offsetting 𝑉𝑐𝑡𝑟𝑙 by approximately 200mV is suggested as a fix.

Vctrl can range from (lower limit at cold temp of -40°C while higher at hot temperatures at 125°C):

  • Before fix: 0.55V to 1.55V
  • After fix: 0.35V to 1.35V

This makes sure that Vctrl operates with robust margin at both hot and cold corners of temperature.