Loop gain adaptation techniques that explore the dynamics of digital phase-locked loops, and clock and data recovery circuits through the autocorrelation function are becoming popular. This work proposes an adaptation technique based on the cross-correlation function between bang-bang phase detector and loop filter outputs instead. Filtering properties of the cross-power spectral density enhance the observability of loop dynamics allowing adaptation while maintaining the phase margin at a safe value. Compared to previously reported methods, the proposed adaptation technique directly tracks the CDR dynamics distinctively enhancing the gain adaptation algorithm.