Signaling improvement using extended transmission lines on 'DIMM'memory modules

摘要

A circuit board (32) such as a memory module board mounts a plurality of memory modules (40) that are electrically connected to a module bus (36) on a first surface of the board (32). The module bus is coupled to a connector (34) at a first end thereof that permits an electrical coupling of a plurality of electrical conductors of the module bus to an external large integrated circuit board, and a terminating resistor device (42) at a second end thereof for properly terminating predetermined ones of the plurality of electrical conductors of the module bus. The module bus (36) is extended beyond the last memory module (40) along the bus by a length which is sufficient to substantially limit reflections and/or crosstalk between the conductors and thereby improve signaling along the module bus. In a first embodiment, the module bus (36) is extended around an edge of the board and for a predetermined distance over any unused portions of the backside of the board (32). In a second embodiment, the module bus is extended for a maximum predetermined distance along any unused portions of the front side of the board (32) when the backside of the board is unavailable for extending the module bus (36). <IMAGE>