JAJSJO2C March 2022 – February 2025 LMK5B33216
PRODUCTION DATA
Enabling Phase Slew Control constrains the output phase transient or phase hit during hitless switching and holdover exit. Users can select DPLLx_PHS1_EN to enable Phase Slew Control to follow the step limits set in DPLLx_PHS1_THRESH and DPLLx_PHS1_TIMER. When transitioning slowly is desired while tracking the new input phase, enabling phase slew control removes the phase cancellation or phase build out based on the programmed timer value and step limits. Similarly when the DPLL switches from APLL-only mode or holdover mode to DPLL Lock Acquisition mode, or hitless switching with two inputs are not frequency-locked the phase slew limits are then applied. When both Phase Cancellation function and Phase Slew Control function are disabled, a phase hit equal to the phase offset between XO and selected input or between the two inputs at the moment of switching are then propagated to the output at a rate determined by the DPLL loop bandwidth. In the case where two inputs are switched but are not frequency-locked Phase Slew Control function can verify that the output smoothly transitions to the new frequency as the rate the defined by the step limits.