ZHCSE74C September 2015 – May 2025 LMK61E2
PRODUCTION DATA
The reference path has a frequency doubler that can be enabled by programming R34.5 = 1. Enabling the doubler allows a higher comparison frequency for the PLL and results in a 3dB reduction in the in-band phase noise at the output of the LMK61E2. Enabling the doubler also results in higher reference and phase detector spurs which is minimized by enabling the higher order components (R3, C3) of the loop filter and programmed to appropriate values. Disabling the doubler results in higher in-band phase noise on the device output than when the doubler is enabled but the reference and phase detector spurs is lower on the device output than when the doubler is enabled.