16.6.7.2.3 Accuracy

There are three main factors that determine the accuracy of Fclkdfll48m. These can be tuned to obtain maximum accuracy when fine lock is achieved.

  • Fine resolution: The frequency step between two Fine values. This is relatively smaller for high output frequencies.
  • Resolution of the measurement: If the resolution of the measured Fclkdfll48m is low, i.e., the ratio between the CLK_DFLL48M frequency and the CLK_DFLL48M_REF frequency is small, then the DFLL48M might lock at a frequency that is lower than the targeted frequency. It is recommended to use a reference clock frequency of 32kHz or lower to avoid this issue for low target frequencies.
  • The accuracy of the reference clock.