Patent Description:
Due to the increasing complexity of electronic components, it is desirable to fit more components in less space on a circuit board or other substrate. Consequently, the spacing between electrical terminals within connectors has been reduced, while the number of electrical terminals housed in the connectors has increased, thereby increasing the need in the electrical arts for electrical connectors that are capable of handling higher and higher speeds and to do so with greater and greater pin densities. It is desirable for such connectors to have not only reasonably constant impedance levels, but also acceptable levels of impedance and cross-talk, as well as other acceptable electrical and mechanical characteristics. Therefore, there remains a need to provide appropriate shielding to preserve signal integrity and to minimize cross-talk as speeds of signals increase and the footprint of the connector remains the same or decreases. A prior art circuit board for use in a modular electrical connector (on which the preamble of claim <NUM> is based) is disclosed in <CIT>. The circuit board includes: (i) a first side with ground and signal traces that extend from adjacent a mating edge to a mounting edge; and (ii) a second side with a ground trace. Press-fit contacts with projections which engage holes through the circuit board and the traces are soldered to the traces. Spaces between the contacts and the adjacent mounting edge are filled with solder when the contacts are soldered to the traces. A similar circuit board for a modular electrical connector is disclosed in <CIT>. Ground and signal traces thereon stop short of a mounting edge thereof and are engaged by tuning-fork shaped contacts.

It would, therefore, be beneficial to provide a connector which reduces cross-talk between signal contact pairs. It would also be beneficial to provide a printed circuit board wafer which increases or maximizes the grounding plane, thereby minimizing the cross-talk between signal contact pairs.

The solution is provided by a circuit board as claimed in claim <NUM> for use in a modular electrical connector.

The invention, which is defined by claim <NUM>, is directed to a circuit board for use in a modular electrical connector. The circuit board has a first surface and an oppositely facing second surface. Signal pathways are provided on the first surface. The signal pathways have signal pathway ends abutting a mounting end of the circuit board. First ground pathways are provided on the first surface. The first ground pathways are positioned adjacent at least one of the signal pathways. The first ground pathways have first ground pathway ends abutting the mounting end of the circuit board. One or more second ground pathways are provided on the second surface. The one or more second ground pathways have second ground pathway ends abutting the mounting end of the circuit board. The positioning of the signal pathway ends abutting the mounting end, the positioning of the first ground pathway ends abutting the mounting end and the positioning of the second ground pathway ends abutting the mounting end minimizes or reduces cross-talk between signal pairs.

An embodiment is directed to a modular electrical connector with a housing having modules positioned therein. The modules have circuit boards. The circuit boards include first surfaces and oppositely facing second surfaces. Signal pathways are provided on the first surfaces. The signal pathways have signal pathway ends abutting mounting ends of the circuit boards. First ground pathways are provided on the first surfaces. Each of the first ground pathways are positioned adjacent at least one of the signal pathways. The first ground pathways have first ground pathway ends abutting the mounting ends of the circuit boards. One or more second ground pathways are provided on the second surfaces. The one or more second ground pathways have second ground pathway ends abutting the mounting ends of the circuit boards. Signal mounting contacts and ground mating contacts are provided at the mating ends of the circuit boards. The positioning of the signal pathway ends abutting the mounting ends, the positioning of the first ground pathway ends abutting the mounting ends and the positioning of the second ground pathway ends abutting the mounting ends reduces cross-talk between differential signal pairs of the signal pathways.

<FIG> illustrates an electrical connector <NUM> formed in accordance with an illustrative embodiment. In the illustrative embodiment, the electrical connector <NUM> is a daughtercard connector that can be mated to a mating backplane connector (not shown) to electrically connect a backplane circuit board (not shown) and a daughtercard circuit board (not shown). While the electrical connector <NUM> is described herein with reference to a daughtercard connector, it is realized that the subject matter herein may be utilized with different types of electrical connectors other than a daughtercard connector. The daughtercard connector <NUM> is merely illustrative of an illustrative embodiment of the type of electrical connector <NUM> that mates with a mating connector.

In the illustrative embodiment shown, the connector <NUM> constitutes a right angle connector wherein a mating end <NUM> and mounting end <NUM> of the connector <NUM> are oriented perpendicular to one another. The connector <NUM> is mounted to the daughtercard circuit board (not shown) at the mounting end <NUM>. The connector <NUM> is mounted to the mating connector (not shown) at the mating end <NUM>. Other orientations of the ends <NUM>, <NUM> are possible in alternative embodiments.

As shown in the illustrative embodiment shown in <FIG>, the connector <NUM> includes a housing <NUM> which is made from a plurality of modules <NUM>. Each of the modules <NUM> has a circuit board or substrate <NUM>.

As shown in <FIG>, each of the substrate <NUM> has a mating end <NUM> configured to mate with the mating connector (not shown) and a mounting end <NUM> which is configured to mount to the daughtercard circuit board (not shown). The substrates <NUM> hold a plurality of individual signal pathways <NUM> which include mating signal contact pads <NUM>, signal traces <NUM> and mounting signal contacts <NUM>. The mating signal contact pads <NUM> are mechanically and electrically connected to the signal traces <NUM> by known methods. The mounting signal contacts <NUM> are mechanically and electrically connected to the signal traces <NUM> by known methods, such as but not limited to soldering, as will be more fully described. The signal pathways <NUM> extend from proximate the mating end <NUM> to the mounting end <NUM>. Ends <NUM> of the signal traces <NUM> are positioned in line or abut the mounting end <NUM> of the substrate <NUM>. In an exemplary embodiment, the signal pathways <NUM> are arranged in pairs carrying differential signals. The individual signal pathways <NUM> are positioned on a first surface <NUM> of the circuit boards <NUM>.

Each of the substrates <NUM> of the modules <NUM> holds a plurality of first ground pathways <NUM> which include mating ground contact pads <NUM>, ground traces <NUM> and mounting ground contacts <NUM>. The mounting ground contacts <NUM> are mechanically and electrically connected to the ground traces <NUM> by known methods, such as but not limited to soldering to a conductive pad of the ground traces <NUM>. The ground pathways <NUM> extend from proximate the mating end <NUM> to the mounting end <NUM>. Ends <NUM> of the ground traces <NUM> are positioned in line or abut the mounting end <NUM> of the substrate <NUM>. The individual ground pathways <NUM> are positioned on the first surface <NUM> of each module <NUM>.

As shown in <FIG>, each of the substrates <NUM> of the modules <NUM> include second ground pathways or traces <NUM> on a second surface <NUM> of each substrate <NUM>. The second surface <NUM> being opposed and spaced from the first surface <NUM>. The ground traces <NUM> extend from proximate the mating end <NUM> to the mounting end <NUM>. Ends <NUM> of the ground traces <NUM> are positioned in line or abut the mounting end <NUM> of the substrate <NUM>.

First openings <NUM> are provided proximate the mounting end <NUM> of the substrate <NUM>. The openings <NUM> are positioned in the signal traces <NUM> and extend from the first surface <NUM> to the second surface <NUM>. In the illustrative embodiment shown, the openings <NUM> are provided in electrical engagement with the signal traces <NUM>, but are not provided in electrical engagement with the ground traces <NUM> on the second surface <NUM>.

Second openings <NUM> are provided proximate the mounting end <NUM> of the substrate <NUM>. The openings <NUM> are positioned in the ground traces <NUM> and extend from the first surface <NUM> to the second surface <NUM>. In the illustrative embodiment shown, the openings <NUM> are provided in electrical engagement with the ground traces <NUM> and the ground traces <NUM> on the second surface <NUM>.

The mounting signal contacts <NUM> have mounting members <NUM> and compliant portions <NUM>. The mounting members <NUM> are configured to be positioned in the openings <NUM> through the first surfaces <NUM> of the substrates <NUM>. The mounting members <NUM> of the mounting signal contacts <NUM> are mechanically and electrically mounted in the openings <NUM> and connected to the signal traces <NUM> by known methods, such as but not limited to soldering, The compliant portions <NUM> are configured to engage the daughtercard (not shown). The compliant portions <NUM> may be, but are not limited to, an eye of the needle pin, although other configurations may be used.

The mounting ground contacts <NUM> have mounting members <NUM> and compliant portions <NUM>. The mounting members <NUM> are configured to be positioned in the openings <NUM> through the first surfaces <NUM> of the substrates <NUM>. The mounting members <NUM> of the mounting ground contacts <NUM> are mechanically and electrically mounted in the openings <NUM> and connected to the ground traces <NUM> and the ground traces <NUM> by known methods, such as but not limited to soldering, The compliant portions <NUM> are configured to engage the daughtercard (not shown). The compliant portions <NUM> may be, but are not limited to, an eye of the needle pin, although other configurations may be used.

The combination of the ground pathways <NUM> and the ground traces <NUM> surround the pairs of signal pathways <NUM>. As the ground pathways <NUM> and the ground traces <NUM> are electrically commoned together, the ground pathways <NUM> and the ground traces <NUM> provide electrical shielding and reduce cross-talk between the pairs of signal pathways <NUM>.

In the illustrative embodiment shown in <FIG>, the housing <NUM> of the connector <NUM> has four modules <NUM> which are positioned adjacent to each other. However, other numbers of modules may be used. Each module <NUM> is spaced from adjacent modules <NUM> to provide mating slots <NUM> for receiving portions of the mating connector.

With the housing <NUM> properly assembled, the ground pathways <NUM> and the ground traces <NUM> of adjacent modules <NUM> extend about the periphery of the pairs of signal pathways <NUM> and surround the pairs of signal pathways <NUM> to provide electrical shielding for the pairs of signal pathways <NUM>. In an exemplary embodiment, entire, <NUM> degree shielding is provided by the ground pathways <NUM> and the ground traces <NUM> along the length of the signal pathways <NUM>. The ground pathways <NUM> and the ground traces <NUM> may control electrical characteristics at the mating ends and throughout the housing <NUM>, such as by controlling cross-talk, signal radiation or other electrical characteristics.

As the ends <NUM> of the signal traces <NUM>, the ends <NUM> of the ground traces <NUM> and the ends <NUM> of the ground traces <NUM> are positioned in line or abut the mounting end <NUM> of the substrate <NUM> the amount of ground that is present on the substrates <NUM> and the connector <NUM> is maximized, which in turn minimizes cross-talk between signal pairs. In addition, as the openings <NUM> and openings <NUM> are positioned proximate to the mounting end <NUM>, the length of the mounting members <NUM> of the mounting signal contacts <NUM> and the length of the mounting members <NUM> of the mounting ground contacts <NUM> is minimized, which also reduces the cross-talk between signal pairs.

As shown in <FIG>, the mounting signal contacts <NUM> have mounting members <NUM> and compliant portions <NUM>. The mounting members <NUM> have signal trace engaging members <NUM> and support members <NUM>. The signal trace engaging members <NUM> are mechanically and electrically mounted and connected to the ends of the signal traces <NUM> by known methods, such as but not limited to soldering. The support members <NUM> extend at approximately right angles to the signal trace engaging members <NUM>. The support members <NUM> have support surfaces <NUM> which cooperate with the mounting end <NUM> of the substrate <NUM> to properly locate the mounting signal contacts <NUM> and to provide support to the substrate <NUM> and the mounting signal contacts <NUM>. The compliant portions <NUM> are configured to engage the daughtercard (not shown). The compliant portions <NUM> may be, but are not limited to, an eye of the needle pin, although other configurations may be used.

The mounting ground contacts <NUM> have mounting members <NUM> and compliant portions <NUM>. The mounting members <NUM> have ground trace engaging members <NUM> and support members <NUM>. The ground trace engaging members <NUM> are mechanically and electrically mounted and connected to the ends of the ground traces <NUM> by known methods, such as but not limited to soldering. The support members <NUM> extend at approximately right angles to the ground trace engaging members <NUM>. The support members <NUM> have support surfaces <NUM> which cooperate with the mounting end <NUM> of the substrate <NUM> to properly locate the mounting ground contacts <NUM> and to provide support to the substrate <NUM> and the mounting ground contacts <NUM>. The compliant portions <NUM> are configured to engage the daughtercard (not shown). The compliant portions <NUM> may be, but are not limited to, an eye of the needle pin, although other configurations may be used.

As shown in <FIG>, the mounting signal contacts <NUM> have mounting members <NUM> and compliant portions <NUM>. The mounting members <NUM> have signal trace engaging members <NUM> and support members <NUM>. The support members <NUM> have support surfaces <NUM> which cooperate with the mounting end <NUM> of the substrate <NUM> to properly locate the mounting signal contacts <NUM> and to provide support to the substrate <NUM> and the mounting signal contacts <NUM>. The support surfaces <NUM> are electrically insulated from the ground surfaces of the substrate <NUM>. Examples of how to provide the insulation include, but are not limited to, removing the ground surface of the substrate <NUM> or adding an insulative surface over the ground surface of the substrate <NUM>. The signal trace engaging members <NUM> extend from the support members <NUM> and are mechanically and electrically mounted and connected to the ends of the signal traces <NUM> by known methods, such as, but not limited to, pressure applied by the compliant beam of the signal trace engaging member <NUM> or by soldering. The compliant portions <NUM> are configured to engage the daughtercard (not shown). The compliant portions <NUM> may be, but are not limited to, an eye of the needle pin, although other configurations may be used.

Claim 1:
A circuit board (<NUM>) for use in a modular electrical connector (<NUM>), the circuit board (<NUM>) comprising:
a first surface (<NUM>) and an oppositely facing second surface (<NUM>);
signal pathways (<NUM>) provided on the first surface (<NUM>), the signal pathways (<NUM>) having signal pathway ends (<NUM>) abutting a mounting end (<NUM>) of the circuit board (<NUM>);
first ground pathways (<NUM>) provided on the first surface (<NUM>), each of the first ground pathways (<NUM>) positioned adjacent at least one of the signal pathways (<NUM>), the first ground pathways (<NUM>) having first ground pathway ends (<NUM>) abutting the mounting end (<NUM>) of the circuit board (<NUM>);
one or more second ground pathways (<NUM>) provided on the second surface (<NUM>), the one or more second ground pathways (<NUM>) having second ground pathway ends (<NUM>) abutting the mounting end (<NUM>) of the circuit board (<NUM>);
wherein the positioning of the signal pathway ends (<NUM>) abutting the mounting end (<NUM>), the positioning of the first ground pathway ends (<NUM>) abutting the mounting end (<NUM>) and the positioning of the second ground pathway ends (<NUM>) abutting the mounting end (<NUM>) reduces cross-talk between signal pairs,
wherein the signal pathways (<NUM>) have mating signal contact pads (<NUM>), signal traces (<NUM>) and mounting signal contacts (<NUM>), the signal traces (<NUM>) extend from proximate a mating end (<NUM>) of the circuit board (<NUM>) to abutting the mounting end (<NUM>) of the circuit board (<NUM>),
wherein the first ground pathways (<NUM>) have first mating ground contact pads (<NUM>), first ground traces (<NUM>) and first mounting ground contacts (<NUM>), the first ground traces (<NUM>) extend from proximate the mating end (<NUM>) to abutting the mounting end (<NUM>) of the circuit board (<NUM>), and
wherein the second ground pathways (<NUM>) have second ground traces (<NUM>), the second ground traces (<NUM>) extend to abut the mounting end (<NUM>) of the circuit board (<NUM>),
characterised in that the second ground traces (<NUM>) extend from proximate and along an edge of the mating end (<NUM>) of the circuit board (<NUM>).