Rambus Inc.
CIRCUITS AND METHODS FOR SAMPLE TIMING IN CORRELATED AND UNCORRELATED SIGNALING ENVIRONMENTS

Abstract:

A memory controller conveys a clock signal with command and address signals to a registered clock driver (RCD) on a memory module. A controller-side chip interface on the RCD supports both source-synchronous and filtered clocking for receipt of the command and address signals, the selection between the two clocking schemes dependent upon the noise environment impacting the clock and command/address signals. If the noise is predominantly correlated, then the chip interface is placed in a source-synchronous clocking mode. If the noise is predominantly uncorrelated, then the chip interface is placed in a filtered clocking mode that filters out uncorrelated noise from the clock signal.