Linear Technology Corporation

Linear Technology Holding LLC

Richard William Ezell

Jan-Michael Stevenson

Michael Dean Womac

Eric Wright Mumper

The subject technology provides for removing a source of delay in a phase-locked loop (PLL) by causing the output rising edge to occur at the same time as the input rising edge. The subject technology replicates the amount of delay experienced along an input reference signal path to the PLL as close as possible using a same circuit configuration and bias circuits as in the input reference signal path. For example, a timing alignment circuit containing a replica circuit adds compensation delay to a negative feedback loop signal to match the feedback loop delay with the reference path delay. The delay of the reference signal path is estimated and added into the replica circuit. The delay characteristics of these two paths negate one another such that the phases of the input reference signal and the feedback loop signal become phase-locked at the input to the PLL.

Multi-chip timing alignment to a common reference signal

A method synchronizes clock signals generated by a system that includes multiple PLLs that are connected in parallel and output frequency dividers driven by the PLLs. The system receives a common frequency reference signal and a common synchronization signal. Each PLL may have a reference signal frequency divider. The reference frequency divider may be phase-reset, for example, by a transition to a first logic state in the synchronization signal, and the output frequency dividers are each phase-reset, for example, by a transition to a second logic state following the transition to the first logic state in the synchronization signal. The transition to the first logic state may be, for example, a rising edge.

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Lucas, TX, United States of America

Richard William Ezell