Patent Description:
Typically, the daughter card to a backplane connection is based on a pin and a socket interface which limits the ability to maintain a controlled impedance in a ruggedized connection system. Other types of connectors to connect the daughter card to the backplane include a right angle electrical connector, a right angle daughter card receptacle, or a right angle orthogonal daughter card receptacle that may house one or more electrically conductive contacts that have a mating end to establish a conductive connection between printed circuit boards. Generally, these connectors limit conventional ruggedized systems to speeds of <NUM> Gb/s and are prone to speed issues. The speed issues are related to signal reflections, crosstalk, differential skew and jitter. Furthermore, these connectors do not usually allow for a modular connection to accommodate varying applications.

Accordingly, there is a need for a connector, a device and/or an assembly that eliminates the conventional pin and socket or card edge interface to provide a ruggedized system that also supports high speed signal transmission as well as a modular connection to allow flexible accomodation of varying applications. <CIT> discloses a spring probe connector comprising a hollow barrel with a first and second opening, a plunger having a contact tip that protrudes from the first opening, a spring positioned within the hollow barrel, and the second opening forming a contact end that is configured to connect with a printed circuit board, wherein the contact end comprises cuts configured to engage an edge of the printed circuit board. <CIT> discloses a method and apparatus for real time output monitoring of light sources and flexible sensitivity adjustment of light sensors. <CIT> discloses a probe pin and method of manufacturing the same. <CIT> discloses a high-speed electrical connector.

The invention is as defined in independent claim <NUM>. Preferred features are defined in the dependent claims.

Also described is an example spring probe connector device for a modular connector assembly that connects to a backplane. The spring probe connector device may include a carrier for providing an interface to the backplane. The carrier may hold an array of a plurality of spring probes, each spring probe of the plurality of spring probes may retract and maintain an electrical connection with the backplane when a force is applied.

Also described is an example modular card assembly that interconnects with a backplane. The modular card assembly may include a spring probe connector device that has a first plurality of spring probes that each retract and maintain an electrical connection with the backplane when a force is applied. The modular card assembly may include a plurality of complaint pin clips, a second plurality of spring probes, or a solder tail. The modular card assembly may include a printed circuit board having one or more traces that connect the spring probe connector device to the plurality of spring clips, the second plurality of spring probes, or the solder tail. The plurality of spring clips, the second plurality of spring probes, and/or the solder tail may electrically connect with another printed circuit board.

Other systems, methods, features, and advantages of the present disclosure will be apparent to one skilled in the art upon examination of the following figures and detailed description. Component parts shown in the drawings are not necessarily to scale, and may be exaggerated to better illustrate the important features of the present disclosure.

Disclosed herein are systems, devices and assemblies for a spring probe connector that interconnects a daughter card with a backplane. The spring probe connector allows for a ruggedized connector that interconnects a modular connector assembly, such as a daughter card or any other printed circuit board, with the backplane. The spring probe connector may provide an interface that connects the modular connector assembly with the backplane and/or another printed circuit board (PCB), such as a motherboard. The modular connector assembly with the spring probe connector may be used in a ruggedized system for use in a military application and/or system that may encounter or be exposed to high vibration environments. Particular embodiments of the subject matter described in this specification may be implemented to realize one or more of the following advantages. The spring probe connector provides an interface that electrically connects the modular connector assembly with the backplane in a ruggedized system, such as for military, aerospace, space or other ruggedized computer/electronic control system applications. The spring probe connector is configured to withstand these high vibration environments.

Other benefits and advantages of the spring probe connector include having a flexible spring probe plunger. The spring probe connector is flexible and/or retractable while providing and maintaining an electrical connection between the backplane and an attached printed circuit board when the back plane presses against the spring probe pin or plunger. The spring probe connector is configured to electrically connect the backplane and the modular connector assembly and maintain the electrical connection, even when the backplane is mis-aligned with the modular connector assembly.

Another benefit and advantage of the spring probe connector is that the spring probe connector controls impedance across the interface with the backplane which allows the spring probe connector to support data transfer speeds between <NUM> Gb/s to <NUM> Gb/s in a ruggedized environment and eliminates the standard pin and socket interface which limits the ability to maintain a controlled impedance. This facilitates a higher level of performance for high speed signal transmission and provides flexible customization based on the particular application.

Other benefits and advantages include using the spring probe connector and vertical interconnect access (VIA) to connect one or more traces of a printed circuit board. The use of a spring probe and VIA to connect the traces costs less than the pin and socket design and is more robust when a connected printed circuit board moves relative to the backplane. A typical pin and socket design may over-deflect or otherwise be bent when the connected printed circuit board moves. The typical design has a thermal or "wedge-lock" card guide, which indexes the daughter card sideways to ensure solid contact between the daughter card's supporting heat sink and the frame of the electronics unit. This indexing or lateral displacement is difficult with the pin engaged in a mating socket contact in the connector. Spring probes, however, simply slide laterally on the target contact's surface to ensure contact.

Finally, the spring probe connector eliminates the backplane connector side component and allows use of a blind VIA on a thicker backplane printed circuit board. The replacement of the existing plated through holes with a blind VIA reduces the capacitance and aids in maintaining an approximate <NUM> ohm impedance. The VIA also allows for controlled impedance and trace routing in the backplane with fewer layers and lower cost.

Conventional pin and socket interfaces typically use one or more pins of <NUM> inches (<NUM>) in diameter with an unsupported length of <NUM> inches (<NUM>) minimum. This is compared to an exposed "plunger" of the same diameter, unsupported for < <NUM> inches (<NUM>) length.

<FIG> shows a spring probe connector ("spring probe") <NUM>. The spring probe <NUM> may electrically connect to a backplane and a printed circuit board of a modular connector assembly. The spring probe <NUM> may include a spring probe plunger ("plunger") <NUM>, a hollow barrel <NUM>, and a printed circuit board (PCB) contact end ("contact end") <NUM>.

An electrical signal may be first received from a backplane by the plunger <NUM> and transmitted to the hollow barrel <NUM> via the electrical connection between the plunger <NUM> and the hollow barrel <NUM>. The electrical signal may then be received by the contact end <NUM> via the electrical connection between the hollow barrel <NUM> and the contact end <NUM>. The electrical signal may then be received by a printed circuit board of a modular connector assembly from the contact end <NUM> via the electrical connection between the contact end <NUM> and the printed circuit board.

Similarly, an electrical signal may be first received from a printed circuit board of a modular connector assembly by the contact end <NUM> and transmitted to the hollow barrel <NUM> via an electrical connection between the contact end <NUM> and the hollow barrel <NUM>. The electrical signal may then be received by the plunger <NUM> via the electrical connection between the plunger <NUM> and the hollow barrel <NUM>. The electrical signal may then be received by a backplane from the plunger <NUM> via the electrical connection between the plunger <NUM> and the backplane.

The spring probe <NUM> may include a hollow barrel <NUM> that defines a first opening <NUM> and a second opening <NUM>. The first opening <NUM> and the second opening <NUM> may be aligned along a longitudinal axis A'. In some embodiments, the first opening <NUM> may be positioned opposite the second opening <NUM>. The hollow barrel <NUM> may be manufactured from liquid crystal polymer (LCP). The hollow barrel <NUM> is depicted as having a circular cross section. However, other cross sectional configurations may be used interchangeably according to various embodiments. The hollow barrel <NUM> may have an outer surface <NUM> and an inner surface <NUM> (shown in <FIG>). In some embodiments, at least some of the inner surface <NUM> may be electrically conductive.

The hollow barrel <NUM> may include a shoulder or flange <NUM> to prevent setback of the spring probe <NUM> when the spring probe <NUM> is placed in a carrier <NUM> (shown in <FIG>). However, other configurations to prevent setback of the spring probe <NUM> may be used interchangeably according to various embodiments.

The spring probe <NUM> may include a plunger <NUM> that is configured to be received by the first opening <NUM> of the hollow barrel <NUM>. The plunger <NUM> may be at least in partial contact with the inner surface <NUM> of the hollow barrel <NUM>. For example, the plunger <NUM> may be slideably engaged with the inner surface <NUM> of the hollow barrel <NUM>. The plunger <NUM> may have a contact tip <NUM> that protrudes from the first opening <NUM>. The contact tip <NUM> may be configured to make electrical contact with a backplane. The plunger <NUM> may be manufactured from a copper alloy. For example, the plunger <NUM> may be manufactured from a beryllium copper and/or phosphorous bronze alloy. In some embodiments, at least a portion of the plunger <NUM> may be coated with a conductive substance. For example, the plunger <NUM> may be coated with an alloy containing copper, nickel, and gold. The plunger <NUM> is depicted as having a circular cross section. However, other cross sectional configurations may be used interchangeably according to various embodiments.

A crimp <NUM> in the hollow barrel <NUM> may be included to retain the plunger <NUM> within the hollow barrel <NUM>. However, other configurations to retain a plunger <NUM> may be used interchangeably according to various embodiments.

The spring probe <NUM> may include one or more springs 114a and 114b (marked in <FIG>) positioned within the hollow barrel <NUM>. The one or more springs 114a and 114b may be configured to apply a spring load ("load") onto the plunger <NUM> along the longitudinal axis A'. The plunger <NUM> may be configured to retract into the hollow barrel <NUM> and maintain an electrical connection with the backplane when a force is applied onto the plunger <NUM>. The force applied onto the contact tip <NUM> and/or the plunger <NUM> may at least be partially aligned along the longitudinal axis A' and opposite the load applied by the one or more springs 114a and 114b.

The one or more springs 114a and 114b retract and/or compress inward into the hollow barrel <NUM> when a force is applied to the contact tip <NUM> and/or the plunger <NUM> which causes the plunger <NUM> to retract into the hollow barrel <NUM>. The force may be caused, for example, by the upward-downward and/or sideward motion when an attached or connected printed circuit board is slid into a backplane.

The spring probe <NUM> may include a contact end <NUM> that protrudes from the second opening <NUM> of the hollow barrel <NUM>. The contact end <NUM> may be configured to connect with an edge of a printed circuit board <NUM> (shown in <FIG>) of a modular connector assembly. In some embodiments, the contact end <NUM> may be spring biased so as to more tightly connect with the edge of the printed circuit board <NUM>.

The contact end <NUM> may be configured to contain the one or more springs 114a and 114b within the hollow barrel <NUM>. The contact end <NUM> may be manufactured from a copper alloy. For example, the contact end <NUM> may be manufactured from a beryllium copper and/or phosphorous bronze alloy. In some embodiments, at least a portion of the contact end <NUM> may be coated with a conductive substance. For example, the contact end <NUM> may be coated with an alloy containing copper, nickel, and gold. The contact end <NUM> and the plunger <NUM> may extend along the longitudinal axis A'.

The features of the spring probe <NUM> may be utilized with any embodiment of spring probe disclosed herein.

<FIG> shows an embodiment of a spring probe connector ("spring probe") <NUM>. The spring probe <NUM> may connect to a backplane and a printed circuit board of a modular connector assembly. The spring probe <NUM> may include a spring probe plunger ("plunger") <NUM>, a hollow barrel <NUM>, and a contact end <NUM>.

The plunger <NUM> may be configured similarly as the plunger <NUM> discussed in regard to <FIG> and may include similar features as the plunger <NUM> discussed in regard to <FIG>. The contact tip <NUM> may be configured similarly as the contact tip <NUM> discussed in regard to <FIG> and may include similar features as the contact tip <NUM> discussed in regard to <FIG>. The hollow barrel <NUM> may be configured similarly as the hollow barrel <NUM> discussed in regard to <FIG> and may include similar features as the hollow barrel <NUM> discussed in regard to <FIG>. The spring probe <NUM> may include one or more springs 214a and 214b (shown in <FIG>) that are configured similarly as the one or more springs 114a and 114b discussed in regard to <FIG> and may include similar features as the one or more springs 114a and 114b discussed in regard to <FIG>. The contact end <NUM> may be configured similarly as the contact end <NUM> discussed in regard to <FIG> and may include similar features as the contact end <NUM> discussed in regard to <FIG>.

<FIG> depict the contact end <NUM> having three engagement arms (208a, 208b, and 208c), however any number of engagement arms may be used interchangeably according to various embodiments. The engagement arms 208a, 208b, and 208c may be configured to engage with different sides of an edge of a printed circuit board <NUM> (shown in <FIG>) of a modular connector assembly. The printed circuit board <NUM> may have a posterior side and an interior side. That is, the printed circuit board <NUM> may be double sided.

The engagement arms 208a and 208b may be posterior engagement arms that may engage with a posterior edge <NUM> of the printed circuit board <NUM> (shown in <FIG>) of a modular connector assembly. The engagement arm 208c may be an anterior engagement arm that may engage with an anterior edge <NUM> of the printed circuit board <NUM> (marked in <FIG>) of a modular connector assembly.

The contact end <NUM> may have a central portion <NUM> (shown in <FIG>). In some embodiments, the engagement arms 208a, 208b, and 208c may connect to each other via the central portion <NUM>. The central portion <NUM> may extend within the hollow barrel <NUM> and may be in electrical contact with the inner surface of the hollow barrel <NUM>, such as the inner surface <NUM> depicted in <FIG>.

As depicted in <FIG>, the engagement arms 208a, 208b, and 208c may include inwardly facing curved portions <NUM> that contact the edge of the printed circuit board <NUM> (shown in <FIG>). However, the engagement arms may be straight ("slotted") according to various embodiments. For example, the engagement arms may be slotted to form a U-shaped channel. In other embodiments, the engagement arms may be duckbill shaped.

As depicted in <FIG>, the engagement arms 208a, 208b, and 208c may also include outwardly facing curved portions <NUM>. The outwardly facing curved portions <NUM> may assist a user in aligning the spring probe <NUM> with the edge of the printed circuit board <NUM> of a modular connector assembly. In some embodiments, at least one of the engagement arms 208a, 208b, and 208c may be spring biased.

The posterior engagement arms 208a and 208b may be spaced from each other by a distance <NUM>. In order to provide a clearance for the anterior engagement arm 208c, the distance <NUM> may have a width that is as wide as or wider than the width <NUM> of the anterior engagement arm 208c. In some embodiments, the posterior engagement arms 208a and 208b may be separated from the anterior engagement arm 208c by a resting distance. The resting distance may be as wide as or wider than the width of the edge of the printed circuit board <NUM> (shown in <FIG>).

In other embodiments, when the engagement arms 208a, 208b, and 208c are spring biased, the resting distance may be thinner than the width of the edge of the printed circuit board <NUM>. For example, the engagement arms 208a, 208b, and 208c may move away from the resting position when the engagement arms 208a, 208b, and 208c engage the edge of the printed circuit board <NUM> so as to more tightly connect with the edge of the printed circuit board <NUM>.

In some embodiments, the posterior engagement arms 208a and 208b may be as wide as the width <NUM> of the anterior engagement arm 208c. In other embodiments, the posterior engagement arms 208a and 208b may be thinner than the width <NUM> of the anterior engagement arm 208c in order to occupy less space.

The contact end <NUM> may include a shoulder or flange <NUM> to prevent setback of the contact end <NUM> when the spring probe <NUM> is placed in a carrier <NUM> (marked in <FIG>). However, other configurations to prevent setback of the spring probe <NUM> may be used interchangeably according to various embodiments.

<FIG> show a spring probe connector device ("connector device") <NUM> for a modular connector assembly that connects to a backplane. The connector device <NUM> includes a carrier <NUM> and a plurality of spring probes including spring probe <NUM> from <FIG>.

The carrier <NUM> may have the plurality of spring probes arranged in an array or a matrix. The carrier <NUM> may provide an interface to connect multiple printed circuit boards with a backplane. The carrier <NUM> may hold multiple spring probes that may be aligned in an array that has one or more rows and/or one or more columns. Each column of one or more rows of the spring probes interface with an edge of a single printed circuit board. Thus, the spring probe connector device <NUM>, using one or more spring probes, may have multiple columns of one or more rows of spring probes that connect with multiple printed circuit boards to provide an interface with the backplane.

In some embodiments the carrier <NUM> may be manufactured from an insulating plastic. For example, the carrier <NUM> may be manufactured from a liquid crystal polymer (LCP) and may have a dielectric constant supporting an impedance. In some embodiments, the carrier <NUM> may have air or one or more air gaps <NUM> within. The one or more air gaps <NUM> may advantageously allow air to circulate between the one or more spring probes to help mitigate overheating.

The features of the spring probe connector device <NUM> may be utilized with any embodiment of spring probe connector device disclosed herein.

<FIG> shows a close-up view of the interface between the spring probe <NUM> and the printed circuit board <NUM>. As depicted, the posterior engagement arms 208a and 208b engage the posterior edge <NUM> of the printed circuit board <NUM> and the anterior engagement arm 208c engages the anterior edge <NUM> of the printed circuit board <NUM>. In some embodiments, one or more contact pads on the printed circuit board <NUM> may be contact with the engagement arms 208a, 208b, and 208c. For example, the anterior engagement arm 208c may engage with a contact pad on the anterior edge <NUM> of the printed circuit board <NUM>. A conductive plastic <NUM> that is part of the printed circuit board <NUM> may surround and enclose the interface between the spring probe <NUM> and the printed circuit board <NUM>.

<FIG> shows an example of a modular connector assembly <NUM>, such as a high-speed daughter card or other printed circuit board, that interfaces with a backplane.

The modular connector assembly <NUM> includes the spring probe connector device <NUM> from <FIG>, a printed circuit board <NUM>, and a plurality of compliant pin clips <NUM>. The printed circuit board <NUM> may be configured similarly as the printed circuit board <NUM> of <FIG> and may include similar features as the printed circuit board <NUM> of <FIG>.

The modular connector assembly <NUM> interfaces with a backplane using the spring probe connector device <NUM> that has a plurality of spring probes including spring probe <NUM>. The modular connector assembly <NUM> may include a plastic holder <NUM> and one or more compliant pin clips <NUM>.

The printed circuit board <NUM> interfaces with the spring probe connector device <NUM> along a first edge <NUM> to connect the printed circuit board <NUM> to a backplane. One or more printed circuit boards may be received by the contact ends, such as contact end <NUM>, of the plurality of spring probes within the spring probe connector device <NUM>. The plurality of spring probes of the spring probe connector device <NUM> deflect and make contact with the backplane when the printed circuit board <NUM> is pushed into a card slot within the backplane. This advantageously allows the modular connector assembly <NUM> to maintain an electrical connection with the backplane even though one or more connectors on the backplane may be misaligned with the modular connector assembly <NUM>.

The printed circuit board <NUM> may interface with a plastic holder <NUM> along a second edge <NUM> of the printed circuit board <NUM>. The second edge <NUM> may be at a right angle to the first edge <NUM>. The plastic holder <NUM> may receive one or more compliant pin clips <NUM>, e.g., an eye of the needle press-fit compliant pin. The eye of the needle press-fit compliant pin may collapse when pushed or moved into a printed circuit board hole to connect to a backplane or other printed circuit board. In some embodiments, the plastic holder <NUM> may be another plastic carrier. The plastic holder <NUM> may hold one or more spring probes, instead of the one or more compliant pin clips <NUM>, to provide an interface between the printed circuit board <NUM> and the backplane or other printed circuit board. In some embodiments, the printed circuit board <NUM> may interface using a solder tail or other PCB interface to the backplane. In other embodiments, the compliant pin clips <NUM>, one or more spring probes, and/or a solder tail may be directly attached to the printed circuit board <NUM>.

The printed circuit board <NUM> may have a posterior side <NUM> and an anterior side <NUM>. That is, the printed circuit board <NUM> may be a double-sided printed circuit board that has one or more traces or transmission lines ("traces") <NUM> that run on the posterior side <NUM>, the anterior side <NUM> or both sides. The posterior side <NUM> may be opposite the anterior side <NUM> on a double-sided printed circuit board.

The one or more traces <NUM> provide a signal path from the one or more contact ends, such as the contact end <NUM>, of the one or more spring probes, such as <NUM>, to the one or more compliant pin clips <NUM>. Each contact end may connect to a corresponding compliant pin clip <NUM> via a trace <NUM>. On a double-sided printed circuit board, a trace on the posterior side <NUM> of the printed circuit board has a corresponding trace on the anterior side <NUM> of the printed circuit board so that the distance and time the signal takes to travel back and forth along the posterior side <NUM> and the anterior side <NUM> side is the same. By sending the signal on a posterior trace on the posterior side <NUM> and returning the signal on an anterior trace on the anterior side <NUM>, the electromagnetic energy that is radiated may be minimized.

In other embodiments, a trace on the anterior side <NUM> of the printed circuit board has a corresponding trace on the posterior side <NUM> of the printed circuit board so that the distance and time the signal takes to travel back and forth along the anterior side <NUM> and the posterior side <NUM> is the same. By sending the signal on an anterior trace on the anterior side <NUM> and returning the signal on a posterior trace on the posterior side <NUM>, the electromagnetic energy that is radiated may be minimized.

The features of the modular connector assembly <NUM> may be utilized with any embodiment of modular connector assembly disclosed herein.

The modular connector assembly <NUM> includes a printed circuit board <NUM>, a plurality of spring probe connectors <NUM>, and a plurality of compliant pin clips <NUM>. The printed circuit board <NUM> may be configured similarly as printed circuit boards <NUM> and <NUM> discussed in regard to <FIG> and <FIG> and may include similar features as the printed circuit boards <NUM> and <NUM> discussed in regard to <FIG> and <FIG>. The plurality of spring probe connectors <NUM> may be configured similarly as the spring probe connectors <NUM> and <NUM> discussed in regard to <FIG>, <FIG>, <FIG>, <FIG>, and <FIG> and may include similar features as the spring probe connectors <NUM> and <NUM> discussed in regard to <FIG>, <FIG>, <FIG>, <FIG>, and <FIG>.

The one or more springs 614a and 614b may be configured similarly as the one or more springs 114a, 114b, 214a, and 214b discussed in regard to <FIG>, <FIG>, and <FIG>, and may include similar features as the one or more springs 114a, 114b, 214a, and 214b discussed in regard to <FIG>, <FIG>, and <FIG>. The plurality of compliant pin clips <NUM> may be configured similarly as the plurality of complaint pin clips <NUM> discussed in regard to <FIG> and may include similar features as the plurality of complaint pin clips <NUM> discussed in regard to <FIG>.

As depicted, the contact ends <NUM> form a U-shaped channel to receive the printed circuit board <NUM>. In some embodiments the contact ends <NUM> may be permanently attached to the printed circuit board <NUM>. In other embodiments, the contact ends <NUM> may be removably attached to the printed circuit board <NUM>.

The plurality of compliant pin clips <NUM> have a forked interface that includes a posterior fork arm <NUM> and an anterior fork arm <NUM>. The posterior fork arm <NUM> may engage with the posterior side <NUM> of the printed circuit board <NUM> of the modular connector assembly <NUM>. The anterior fork arm <NUM> may engage with the anterior side <NUM> of the printed circuit board <NUM> of the modular connector assembly <NUM>. In some embodiments, the plastic holder <NUM> may pinch the posterior fork arm <NUM> and the anterior fork arm <NUM> to engage the printed circuit board <NUM>. In other embodiments, the compliant pin clips <NUM> may engage with a slot attached to the printed circuit board <NUM>. For example, the posterior fork arm <NUM> and the anterior fork arm <NUM> may engage with an inner surface of the slot attached to the printed circuit board <NUM>.

<FIG> shows a modular connector assembly <NUM> having a first printed circuit board 705a and a second printed circuit board 705b.

The modular connector assembly <NUM> includes a first printed circuit board 705a and a second printed circuit board 705b, a first plurality of compliant pin clips 706a, a second plurality of complaint pin clips 706b, and a plurality of spring probe connectors <NUM>. The first printed circuit board 705a and the second printed circuit board 705b may be configured similarly as the printed circuit boards <NUM>, <NUM>, and <NUM> discussed in regard to <FIG>, <FIG>, and <FIG> and may include similar features as the printed circuit boards <NUM>, <NUM>, and <NUM> discussed in regard to <FIG>, <FIG>, and <FIG>. The plurality of spring probe connector <NUM> may be configured similarly as the spring probe connectors <NUM>, <NUM>, and <NUM> discussed in regard to <FIG>, <FIG>, <FIG>, <FIG>, and <FIG> and <FIG> and may include similar features as the spring probe connectors <NUM>, <NUM>, and <NUM> discussed in regard to <FIG>, <FIG>, <FIG>, <FIG>, and <FIG> and <FIG>.

The first plurality of compliant pin clips 706a and the second plurality of compliant pin clips 706b may be configured similarly as the plurality of complaint pin clips <NUM> and <NUM> discussed in regard to <FIG> and <FIG> and may include similar features as the plurality of complaint pin clips <NUM> and <NUM> discussed in regard to <FIG> and <FIG>.

The features of the modular connector assembly <NUM> may be utilized with any embodiment of the modular connector assembly disclosed herein.

Claim 1:
A spring probe connector (<NUM>, <NUM>, <NUM>) configured to connect to a backplane and a printed circuit board (<NUM>, <NUM>, <NUM>, <NUM>) of a modular connector assembly (<NUM>, <NUM>, <NUM>, <NUM>), the spring probe connector comprising:
a hollow barrel (<NUM>, <NUM>) defining a first opening (<NUM>) and a second opening (<NUM>);
a plunger (<NUM>, <NUM>) configured to be received by the first opening, the plunger having a contact tip (<NUM>, <NUM>) that protrudes from the first opening and is configured to make electrical contact with the backplane;
one or more springs (<NUM>, <NUM>) positioned within the hollow barrel and configured to apply a load onto the plunger; and
a contact end (<NUM>, <NUM>, <NUM>) that protrudes from the second opening and is configured to engage an edge of the printed circuit board of the modular connector assembly,
wherein the contact end (<NUM>, <NUM>, <NUM>) comprises two posterior engagement arms (208a, 208b) and one anterior engagement arm (208c), the two posterior engagement arms being configured to engage with a posterior edge of the printed circuit board and the anterior engagement arm being configured to engage with an anterior edge of the printed circuit board, and
wherein the two posterior engagement arms (208a, 208b) and the anterior engagement arm (208c) include inwardly facing curved portions (<NUM>) configured to contact the edge of the printed circuit board.