Electronic devices continue to shrink in size, yet increase in speed and complexity. This has lead to the widespread availability of relatively small electronic components capable of driving high-speed signals (e.g., above one GHz) over printed circuit board (PCB) tracks. The increased use of these small, high-speed components has created a significant demand for high performance electrical connectors that can support high frequencies and denser PCB track configurations.
In response to this demand, certain types of high performance electrical connectors have been developed. One type of high performance connector is a GbX® Style connector, available from Molex, Inc. of Lisle, Ill. FIGS. 1-2 are partial top and bottom perspective views, respectively, of a conventional GbX® backplane connector 10.
The backplane connector 10 includes a non-conductive housing having a housing floor 12 with header sidewalls (not shown) extending perpendicularly from the housing floor 12 substantially parallel to each other. The partial views of FIGS. 1-2 show an exemplary 4×2 array of differential pins 13 and three ground plane shields 14 interposed between rows of differential pin pairs 11. Each of the pin pairs 11 can receive or transmit a differential signal. The differential-pair pins 13 and ground shields 14 are press-fitted into the floor 12 so as to pass through the floor 12. Each of the differential pins 13 has a generally flat upper portion 19 and an eye-of-the-needle compliant pin 23 as a lower portion. Each of the ground shields 14 has a generally flat upper blade 15 and one or more lower eye-of-the-needle pins 17.
For purposes of convention, the partial views of FIGS. 1-2 show two “columns” of differential pins 13. Each column has four metal differential pins 13, which are part of a larger column in the two-dimensional differential-pair pin array. Each ground shield 14 is made up of a metal plate 15 and is connected to ground to provide shielding between “rows” of the pin pairs 11.
Transmitting high speed signals over differential pair channels has become an increasingly popular technique for high bandwidth transmission between printed circuit boards (PCBs). In a typical high bandwidth system, “daughter card” PCBs are connected to a “backplane” using mated connectors. The backplane is itself a layered circuit board having, among other things, differential pair tracks formed therein for carrying high frequency signals between daughter cards.
In such systems, a variable that effects transmission bandwidth is crosstalk. Generally, crosstalk is the electrical interference in a channel caused by a signal traveling through a neighboring channel. Under some circumstances, the presence of unwanted crosstalk degrades system performance and negatively impacts bandwidth. Thus, in differential pair systems, it is important that daughter cards and backplanes are designed to reduce the amount of crosstalk between differential pairs. It is also highly desirable to have PCB connectors that reduce crosstalk.
In view of the foregoing, there is a substantial need for an electrical connector that significantly reduces crosstalk in high signal density, high bandwidth applications.
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