Devices and methods to reduce differential signal pair crosstalk

Generally discussed herein are systems, apparatuses, and methods that relate to reducing crosstalk in a differential signal pair. According to an example, a device may include a first pair of differential signal lines comprising a first signal line and a second signal line proximate the first signal line, the first signal line and the second signal line separated from each other along a first line, and a second pair of differential signal lines comprising a third signal line proximate a fourth signal, the third signal line and the fourth signal separated from each other along a second line generally perpendicular to the first line.

TECHNICAL FIELD

Embodiments in this disclosure generally relate to devices and methods for reducing crosstalk between differential signal pairs.

BACKGROUND

Routing in a die and on a Printed Circuit Board (PCB) may be quite complex. Difficulties encountered in routing include managing functional blocks of a circuit or die, different functional blocks running at different frequencies and creating crosstalk, signal degradation, such as high frequency signal degradation, and providing a sufficient ground plane to help in stabilizing sensitive signals, among others. A problem that may cause an error in circuit operation includes crosstalk between differential signal pairs. As electric and electronic components become able to resolve finer differences in a signal, it may become more important to reduce crosstalk between signal lines in a die or a PCB.

DESCRIPTION OF EMBODIMENTS

Embodiments in this disclosure relate generally to reducing crosstalk in a differential signal pair. Methods, systems, or devices in accord with this disclosure may help in reducing the crosstalk between vias, pads, or traces on a PCB or within a chip, among other signal lines.

For a differential signal pair, a signal line in a package or a PCB may pick up noise from another signal line in the package or PCB, such as other nearby differential signal pair signal lines. A PCB may include one or more layers. A layer of the PCB may include a ground potential reference voltage plane. As the frequency requirements for signals in a package or board increase, crosstalk between differential signal pairs may become a bigger problem.

Crosstalk is generally one or more signals on one or more signal lines (e.g., traces, vias, interconnects, pads, pinouts, etc.) creating an undesired effect on one or more other signal lines. Crosstalk may be caused by capacitive, inductive, or conductive coupling between the signal lines. Crosstalk may appear as a frequency present in one signal line, appearing in a signal line that does not normally include that frequency, thus creating additional error in the signal line.

Differential signaling is a method of conveying information in which a difference between voltages on two signal lines determines a value corresponding to the information to be transmitted. As used herein, “pair of differential signal lines” means signal lines used in a differential signaling scheme. Information conveyed using differential signaling may be more resistant to noise than other signaling techniques. This is at least in part, because noise tends to affect each signal line in a pair of differential signal lines equally, and the information to be conveyed is the potential difference between the two signal lines. Thus, if a first signal line of a differential pair has a voltage potential, v, a second signal line of the differential pair has a voltage potential, w, and a noise source adds a voltage potential, x, to the first and second signal lines of the differential pair, the potential difference between the two signal lines does not change even though the actual potential on the signal lines has changed (i.e. |v−w|=|(v+x)−(w+x)|). Differential signaling may be used in analog and digital signaling. Differential signaling is distinguished from single-ended signaling, where single-ended signaling conveys information using a voltage potential on a single signal line.

A previous solution to reducing crosstalk between pairs of differential signal lines includes adding ground signal lines (i.e. a signal line electrically coupled to the ground reference potential) around each differential signal pair. Such a solution increases the overall size of the package or board, which may increase cost in manufacturing. A previous solution may be based on a uniform package Ball Grid Array (BGA) pattern in which there is little or no flexibility to adjust differential signal pair to differential signal pair orientation. A previous solution may include placing pairs of differential signal lines in parallel with respect to each other and placing ground signal lines in between the pairs of differential signal lines.

Discussed herein are devices, techniques, and systems that may reduce crosstalk without adding ground signal lines around or between pairs of differential signal lines. One or more embodiments discussed herein may include a pair of differential signal lines oriented perpendicularly with respect to another pair of differential signal lines, such as without adding ground signal lines. Such embodiments can reduce the crosstalk between differential signal pairs while maintaining or reducing the package size. A simulation has been performed to investigate if the perpendicular layout of differential signal pair signal lines improves (i.e. reduces) crosstalk and the results of the simulation are presented herein.

The inventors have figured out that the crosstalk between differential signal pairs is affected by the orientation of differential signal pairs relative to one another. The inventors have also figured out that zero or near zero crosstalk between differential signal pairs may be achieved by placing the differential signal lines at about ninety degrees relative to each other. Some BGA and other package pinout technology allows the use of variable pitch or “ball anywhere” that allows for a flexible differential signal pair pinout pattern.

FIG. 1Aillustrates, by way of example, a block diagram of a component layout100A. The component layout100A may include a medium102A, such as a die (e.g., a package), a board (e.g., a PCB), or other electrical or electronic circuit layout medium. The medium102A specifies a size, shape, and location of conductive material and/or descriptive material to be arranged on/in the medium102A. The layout100A may be implemented in a physical device, such as a die or board. In the example shown inFIG. 1A, the medium102A is a PCB layout that includes conductive material layout that includes a first pair of differential signal lines104A and104B and a second pair of differential signal lines108A and108B. The descriptive material may include text, outlines, or other material. The descriptive material may help describe a component, layout choice, assembly instruction, or designate a differential signal pair, among others. In the illustrated embodiment100A, the descriptive material includes an outline106that indicates that the lines104A and104B are a differential signal pair, and an outline110that indicates that the lines108A and108B are a differential signal pair. The lines112A and112B are ground signal lines (i.e. lines that are electrically connected to a reference potential designated as ground, such as through a ground plane or other reference potential connection).

The component layout100A includes two differential signal pairs (i.e. a first differential signal pair comprising the lines104A-B and a second differential signal pair comprising the lines108A-B) oriented generally parallel to each other. As used herein, a first differential signal pair being oriented parallel to a second differential pair means that a straight line connecting the centroids of the signal lines of the first differential signal pair generally parallel to a straight line connecting the centroids of the signal lines of the second differential signal pair. As used herein, a first differential signal pair being oriented perpendicular to a second differential pair means that a straight line connecting the centroids of the signal lines of the first differential signal pair is generally perpendicular to a straight line connecting the centroids of the signal lines of the second differential signal pair. “Generally parallel” and “generally perpendicular” mean parallel to within a few degrees and perpendicular to within a few degrees, respectively. The lines114and116connecting the centroids of the first differential signal pair and the second different signal pair are generally parallel to each other.

FIG. 1Billustrates another example of a block diagram of an embodiment of a component layout100B. The component layout100B is similar to the component layout100A with the layout100B including the medium102B and ground signal lines112A and112B between the first pair of differential signal lines104A-B and the second pair of differential signal lines108A-B. The medium102B ofFIG. 1Bis a PCB. Similar to the layout100A, the lines114and116connecting the centroids of the first differential signal pair and the second different signal pair are generally parallel to each other. In contrast to the layout100A, the first pair of differential signal lines104A-B and second pair of differential signal lines108A-B are separated by ground lines112A-B. The differential signal pairs of the layout100B may include less crosstalk than the differential signal pairs of the layout100A. The pairs of differential signal lines of the layouts100A-B are proximate, directly adjacent, and parallel to each other.

FIG. 2illustrates, by way of example, a perspective view diagram of an embodiment of a component layout200. The layout200as illustrated includes a medium202, a first pair of differential signal lines204A, and204B and a second pair of differential signal lines208A and208B. The first pair of differential signal lines includes the line204A and the line204B that is proximate (e.g., closest or most proximate) the line204A. The second pair of differential signal lines includes the line208A and the line208B that is proximate the line208A.

The line214indicates an orientation between centroids of the first pair of differential signal lines204A-B and the line216indicates an orientation between centroids of the second pair of differential signal lines208A-B. The outline206indicates that the signal lines204A-B are a pair of differential signal lines and the outline210indicates the signal lines208A-B are another pair of differential signal lines.

The first pair of differential signal lines204A-B is oriented generally perpendicular to the second pair of differential signal lines208A-B (i.e. the line214is generally perpendicular to the line216). The first pair of differential signal lines204A-B is oriented such that the line214intersects the line216at about the midpoint of the line216(i.e. the first pair of differential signal lines204A-B is situated along an axis about half way between the differential signal lines208A-B). The layout200may include a reduced crosstalk as compared to a crosstalk between pairs of differential signal pairs of other layouts, such as the layouts100A and100B.

FIG. 3illustrates, by way of example, a perspective view diagram of another embodiment of another component layout300. The layout300as illustrated includes a medium302. The medium302may be a PCB, a die (e.g., a package), or other electric or electronic circuit medium. The layout300as illustrated includes a first pair of differential signal lines304A and304B, a second pair of differential signal lines308A and308B, a third pair of differential signal lines308C and308D, a fourth pair of differential signal lines304C and304D, a fifth pair of differential signal lines304E and304F, and a sixth pair of differential signal lines308E and308F. The layout300includes a plurality of ground signal lines312A,312B,312C, and312D.

The signal line304A and the signal line304B are proximate each other and separated from each other along the line314A. The line314A connects the centroids of the signal lines304A-B of the first pair of differential signal lines. Similarly the signal line304C and the signal line304D are proximate each other and separated from each other along the line314B. The line314B connects the centroids of the signal lines304C-D of the fourth pair of differential signal lines. The signal line304E and the signal line304F are proximate each other and separated from each other along the line314C. The line314C connects the centroids of the signal lines304E-F of the fifth pair of differential signal lines. The line314C as illustrated is coextensive with the line314A.

The signal line308A and the signal line308B are proximate each other and separated from each other along the line316A. The line316A connects the centroids of the signal lines308A-B of the second pair of differential signal lines. Similarly the signal line308C and the signal line308D are proximate each other separated from each other along the line316B. The line316B connects the centroids of the signal lines308C-D of the third pair of differential signal lines. The signal line308E and the signal line308F are proximate each other separated from each other along the line316C. The line316C connects the centroids of the signal lines308E-F of the sixth pair of differential signal lines.

The first pair of differential signal lines304A-B is oriented generally perpendicular to the second, third, and sixth pairs of differential signal lines308A-B,308C-D, and308E-F (i.e. the line314A is generally perpendicular to the lines316A,316B, and316C). Similarly, the fourth pair of differential signal lines304C-D and the fifth pair of differential signal lines304E-F are oriented generally perpendicular to the second, third, and sixth pairs of differential signal lines308A-B,308C-D, and308E-F (i.e. the lines314B and314C are generally perpendicular to the lines316A,316B, and316C).

The second pair of differential signal lines308A-B is oriented generally perpendicular to the first, fourth, and fifth pairs of differential signal lines304A-B,304C-D, and304E-F (i.e. the line316A is generally perpendicular to the lines314A,314B, and314C). Similarly, the third pair of differential signal lines308C-D and the sixth pair of differential signal lines308E-F are oriented generally perpendicular to the first, fourth, and fifth pairs of differential signal lines304A-B,304C-D, and304E-F (i.e. the lines316B and316C are generally perpendicular to the lines314A,314B, and314C).

The pairs of differential signal lines304A-B,304C-D,304E-F,308A-B,308C-D, and308E-F may be situated such that another pair of differential signal lines proximate to a respective pair of differential signal lines304A-B,304C-D,304E-F,308A-B,308C-D, and308E-F is oriented generally perpendicular to the respective pair of differential signal lines304A-B,304C-D,304E-F,308A-B,308C-D, and308E-F. InFIG. 3, the second pair of differential signal lines308A-B and the third pair of differential signal lines308C-D may be proximate the first pair of differential signal lines304A-B (i.e. closest to the first pair of differential signal lines as determined by the distance between the centers of the lines314A and316A, and314A and316B); the third pair of differential signal lines308C-D may be proximate the first pair of differential signal lines304A-B, the fourth pair of differential signal lines304C-D, and the fifth pair of differential signal lines304E-F; etc.

The pairs of differential signal lines304A-B,304C-D,304E-F,308A-B,308C-D, and308E-F may be situated such that another pair of differential signal lines immediately adjacent to a respective pair of differential signal lines304A-B,304C-D,304E-F,308A-B,308C-D, and308E-F is oriented perpendicular to the respective pair of differential signal lines304A-B,304C-D,304E-F,308A-B,308C-D, and308E-F. InFIG. 3, the second pair of differential signal lines308A-B and the third pair of differential signal lines308C-D may be immediately adjacent the first pair of differential signal lines304A-B (i.e. closest to the first pair of differential signal lines as determined by the distance between the centers of the lines314A and316A, and314A and316B); the third pair of differential signal lines308C-D may be immediately adjacent the first pair of differential signal lines304A-B, the fourth pair of differential signal lines304C-D, and the fifth pair of differential signal lines304E-F; etc.

The pairs of differential signal lines304A-B,304C-D,304E-F,308A-B,308C-D, and308E-F may be situated such that there are at most four pairs of differential signal pairs within a specified radius of a midpoint of the line connecting the centroids of the pair of differential signal lines, and the pairs of differential signal lines within the radius are oriented generally perpendicular to the pair of differential signal lines304A-B,304C-D,304E-F,308A-B,308C-D, and308E-F. Two of the four pairs of differential signal lines may be situated on either end of the line connecting the centroids and the other two of the four pairs of the differential signal lines may be situated on either side of the midpoint of the line connecting the centroids. The pairs of differential signal lines within the radius, proximate (e.g., most proximate) to, or directly adjacent to a respective pair of differential signal lines are oriented parallel to one another.

These configurations of pairs of differential signal lines may provide sufficient space between pairs of differential signal lines that are oriented generally parallel to each other that the cross talk between them is low, negligible, or near zero. These configurations of pairs of differential signal lines may provide a reduced crosstalk between pairs of differential signal lines by orienting the proximate, directly adjacent, or pairs of differential signal lines within a specified radius of each other (e.g., where the radius is measured from a midpoint of the line connecting the centroids of the pair of differential signal lines) generally perpendicular to one another. A reduction in crosstalk may increase a bandwidth for a given channel or signal line. One or more embodiments discussed herein may also save space, such as to help reduce a package or PCB size.

FIG. 4illustrates, by way of example, a perspective view diagram of another embodiment of a component layout400. The pairs of differential signal lines ofFIG. 4may be oriented relative to each other in a similar manner as discussed with respect to the pairs of differential signal lines ofFIG. 3. The layout400may include a medium402and a plurality of pairs of differential signal lines404A and404B,404C and404D,404E, and404F,404G and404H,408A and408B,408C and408D,408E, and408F, and404G and404H arranged on/in the medium402. The layout400as illustrated includes a plurality of electrical connections418A,418B,418C,418D,418E,418F,418G,418H,418I, and418J. The layout400as illustrated includes outlines406A,406B,406C,406D,410A,410B,410C, and410D.

The medium402specifies a size, shape, and location of conductive material and/or descriptive material to be arranged on/in the medium402. The medium402may be similar to the medium302. The medium402may be a PCB, a die, or other electrical or electronic component medium. In the example shown inFIG. 4, the medium402is a PCB layout that includes a die pinout. The descriptive material may include text, an outline, or other material. The descriptive material may help describe a component, layout choice, assembly instruction, or designate a differential signal pair, among others. In the illustrated embodiment400, the descriptive material includes an outline406A-D and410A-D that indicates that the respective lines404A and404B,404C and404D,404E, and404F,404G and404H,408A and408B,408C and408D,408E, and408F, and404G and404H are pairs of differential signal lines. The signal lines412A,412B,412C, and412D are ground lines (i.e. lines that are electrically connected to a reference potential designated as ground, such as through a ground plane or other ground connection).

The differential signal lines408A and408B mirror the differential signal lines408C and408D. The differential signal lines408A and408B may be vias while the differential signal lines408C and408D are solder pads for a die, or vice versa. Since the same signal is travelling through the signal line408C and408A through the connection418A, crosstalk between the lines is not a concern.

The line416A indicates an axis on which the centroids of the signal lines408A-B lie, and similarly the lines416B,416C, and416D indicate respective axes on which the centroid of the signal lines408C and408D,408E and408F, and408G and408H lie, respectively. The line414A indicates an axis on which the centroids of the signal lines404A and404B lie, and similarly the line414B,414C, and414D indicate respective axes on which the centroid of the signal lines404C and404D,404E and404F, and404G and404H lie, respectively. The lines416A,416B,416C, and416D may be generally parallel to each other and generally perpendicular to the lines414A,414B,414C, and414D.

The signal lines412A,412B,412C, and412D are ground signal lines. The signal line412B is electrically connected to the signal line412A through the connection418J and the signal line412C is electrically connected to the signal line412D through the signal line418I.

The signal lines408C,408D,404A,404B,404E,404F,408G,408H,412B and412C may be vias or pads while the signal lines408A,408B,404C,404D,404G,404H,408E,408F,412A, and412B are pads or vias, respectively. The signal lines408A,408B,404C,404D,404G,404H,408E,408F,412A, and412B may “mirror” and be electrically connected to the signal lines408C,408D,404A,404B,404E,404F,408G,408H,412B and412C, respectively.

FIG. 5illustrates, by way of example, a perspective view diagram of another embodiment of a component layout500. The layout500is similar to the layout300with the layout500including electrical connections518A,518B,518C,518D,518E,518F,518G,518H,518I,518J,518K, and518L connected to the signal lines504A,504B,508A,508B,508C,508D,504C,504D,508E,508F,504E, and504F, respectively.

The layout500as illustrated includes a medium502. The medium502may be a PCB, a die (e.g., a package), or other electric or electronic circuit medium. The layout500as illustrated includes a first pair of differential signal lines504A and504B, a second pair of differential signal lines508A and508B, a third pair of differential signal lines508C and508D, a fourth pair of differential signal lines504C and504D, a fifth pair of differential signal lines504E and504F, and a sixth pair of differential signal lines508E and508F. The layout500includes a plurality of ground signal lines512A,512B,512C, and512D.

The signal line504A and the signal line504B are proximate each other and separated from each other along the line514A. The line514A connects the centroids of the signal lines504A-B of the first pair of differential signal lines. Similarly the signal line504C and the signal line504D are proximate each other and separated from each other along the line514B. The line514B connects the centroids of the signal lines504C-D of the fourth pair of differential signal lines. The signal line504E and the signal line504F are proximate each other and separated from each other along the line514C. The line514C connects the centroids of the signal lines504E-F of the fifth pair of differential signal lines.

The signal line508A and the signal line508B are proximate each other and separated from each other along the line516A. The line516A connects the centroids of the signal lines508A-B of the second pair of differential signal lines. Similarly the signal line508C and the signal line508D are proximate each other and separated from each other along the line516B. The line516B connects the centroids of the signal lines508C-D of the third pair of differential signal lines. The signal line508E and the signal line508F are proximate each other and separated from each other along the line516C. The line516C connects the centroids of the signal lines508E-F of the sixth pair of differential signal lines.

The first pair of differential signal lines504A-B is oriented generally perpendicular to the second, third, and sixth pairs of differential signal lines508A-B,508C-D, and508E-F (i.e. the line314A is generally perpendicular to the lines516A,516B, and516C). Similarly, the fourth pair of differential signal lines504C-D and the fifth pair of differential signal lines504E-F are oriented perpendicular to the second, third, and sixth pairs of differential signal lines508A-B,508C-D, and508E-F (i.e. the lines514B and514C are generally perpendicular to the lines516A,516B, and516C).

The second pair of differential signal lines508A-B is oriented generally perpendicular to the first, fourth, and fifth pairs of differential signal lines504A-B,504C-D, and504E-F (i.e. the line516A is generally perpendicular to the lines514A,514B, and514C). Similarly, the third pair of differential signal lines508C-D and the sixth pair of differential signal lines508E-F are oriented perpendicular to the first, fourth, and fifth pairs of differential signal lines504A-B,504C-D, and504E-F (i.e. the lines516B and516C are generally perpendicular to the lines514A,514B, and514C).

The pairs of differential signal lines504A-B,504C-D,504E-F,508A-B,508C-D, and508E-F may be situated such that another pair of differential signal lines proximate to a respective pair of differential signal lines504A-B,504C-D,504E-F,508A-B,508C-D, and508E-F is oriented perpendicular to the respective pair of differential signal lines504A-B,504C-D,504E-F,508A-B,508C-D, and508E-F. InFIG. 5, the second pair of differential signal lines508A-B and the third pair of differential signal lines508C-D may be proximate the first pair of differential signal lines504A-B (i.e. closest to the first pair of differential signal lines as determined by the distance between the centers of the lines514A and516A, and514A and516B); the third pair of differential signal lines508C-D may be proximate the first pair of differential signal lines504A-B, the fourth pair of differential signal lines504C-D, and the fifth pair of differential signal lines504E-F; etc.

The pairs of differential signal lines504A-B,504C-D,504E-F,508A-B,508C-D, and508E-F may be situated such that another pair of differential signal lines immediately adjacent to a respective pair of differential signal lines504A-B,504C-D,504E-F,508A-B,508C-D, and508E-F is oriented perpendicular to the respective pair of differential signal lines504A-B,504C-D,504E-F,508A-B,508C-D, and508E-F. InFIG. 5, the second pair of differential signal lines508A-B and the third pair of differential signal lines508C-D may be immediately adjacent the first pair of differential signal lines504A-B (i.e. closest to the first pair of differential signal lines as determined by the distance between the centers of the lines514A and516A, and514A and516B); the third pair of differential signal lines508C-D may be immediately adjacent the first pair of differential signal lines504A-B, the fourth pair of differential signal lines504C-D, and the fifth pair of differential signal lines504E-F; etc.

The pairs of differential signal lines504A-B,504C-D,504E-F,508A-B,508C-D, and508E-F may be situated such that there are at most four pairs of differential signal pairs within a specified radius of a midpoint of the line connecting the centroids of the pair of differential signal lines, and the pairs of differential signal lines within the radius are oriented generally perpendicular to the pair of differential signal lines504A-B,504C-D,504E-F,508A-B,508C-D, and508E-F. Two of the four pairs of differential signal lines may be situated on either end of the line connecting the centroids and the other two of the four pairs of the differential signal lines may be situated on either side of the midpoint of the line connecting the centroids. The pairs of differential signal lines within the radius, proximate (e.g., most proximate) to, or directly adjacent to a respective pair of differential signal lines are oriented parallel to one another.

The component layout200,300,400, or500may be implemented in a device, such as a PCB, die (e.g., a package), a semiconductor substrate, or other electrical or electronic component medium. The component layout200,300,400, or500may be created using a computer program, such as a routing program, a layout program, or other program. The medium include a pin grid array (PGA), a BGA package, a Land Grid Array (LGA) package, a dual in-line package (DIP), a leadless chip carrier (LCC), a quad flat pack (QFP), a thin small outline package (TSOP), a system in package (SIP), a multi-chip module (MCM), a system on chip (SoC), or other package structure.

Two signal lines being “proximate” one another means that no other signal line is closer to the signal lines that are proximate one another. For example, if the signal lines are vias, no other vias is closer to either via than the vias that are proximate one another.

FIG. 6illustrates, by way of example, a graph600of noise versus frequency for various component layouts100A,100B, and200. The graph600was produced by simulating noise (crosstalk) in the various layouts100A,100B, and200. The graph600shows that the noise level in decibels is lower for the layout200for all frequencies up to thirty Gigahertz (as simulated).

FIG. 7illustrates, by way of example, a flow diagram of an embodiment of a method. The method700as illustrated includes: situating a first pair of differential signal lines on or at least partially in a medium at operation702, and situating a second pair of differential signal lines on or at least partially in the medium such that the second pair of differential signal lines is oriented perpendicular to the first pair of differential signal lines at operation704. The first pair of differential signal lines may include a first signal line proximate a second signal line. The first signal and the second signal line separated from each other along a first line. The second pair of differential signal lines may include a third signal line proximate a fourth signal line. The third signal line and the fourth signal line may be separated from each other along a second line generally perpendicular to the first line.

The method700may include situating a third pair of differential signal lines comprising a fifth signal proximate a sixth signal on or at least partially in the medium, the fifth signal and the sixth signal line separated from each other along a third line generally parallel to the first line and generally perpendicular to the second line. The method700may include situating a fourth pair of differential signal lines comprising a seventh signal line proximate an eighth signal line on or at least partially in the medium, the seventh signal and the eighth signal separated from each other along a fourth line generally perpendicular to the first line, generally parallel to the second line, and generally perpendicular to the third line. The method700may include situating a third pair of differential signal lines including a fifth signal line and a sixth signal line on or at least partially in the medium, wherein the fifth and sixth signal lines are separated from each other along a line parallel to the first line. The method700may include electrically coupling the fifth signal line to the first signal line and the sixth signal line to the second signal line.

Examples and Notes

The present subject matter may be described by way of several examples.

Example 1 may include or use subject matter (such as an apparatus, a method, a means for performing acts, or a device readable memory including instructions that, when performed by the device, may cause the device to perform acts), such as may include or use a first pair of differential signal lines comprising a first signal line and a second signal line proximate the first signal line, the first signal line and the second signal line separated from each other along a first line; and a second pair of differential signal lines comprising a third signal line proximate a fourth signal, the third signal line and the fourth signal separated from each other along a second line generally perpendicular to the first line.

Example 2 may include or use, or may optionally be combined with the subject matter of Example 1 to include or use, wherein the first line connects the centroids of the first and second signal lines and intersects the second line between the third and fourth signal lines.

Example 3 may include or use, or may optionally be combined with the subject matter of at least one of Examples 1-2 to include or use a third pair of differential signal lines comprising a fifth signal line proximate a sixth signal line, the fifth signal line and the sixth signal line separated from each other along a third line generally parallel to the first line and generally perpendicular to the second line.

Example 4 may include or use, or may optionally be combined with the subject matter of Example 3 to include or use, wherein the second line connects the centroids of the third and fourth signal lines and intersects the third line between the fifth and sixth signal lines.

Example 5 may include or use, or may optionally be combined with the subject matter of at least one of Examples 3-4 to include or use a fourth pair of differential signal lines comprising a seventh signal line proximate an eighth signal line, the seventh signal line and the eighth signal line separated from each other along a fourth line generally perpendicular to the first line, generally parallel to the second line, and generally perpendicular to the third line.

Example 6 may include or use, or may optionally be combined with the subject matter of Example 5 to include or use, wherein the fourth line connects the centroids of the seventh and eighth signal lines and intersects the first line between the first and second signal lines.

Example 7 may include or use, or may optionally be combined with the subject matter of at least one of Examples 5-6 to include or use one or more ground signal lines situated in a region between the first, second, third, and fourth pairs of differential signal lines.

Example 8 may include or use, or may optionally be combined with the subject matter of at least one of Examples 1-7 to include or use, wherein the device includes a memory device.

Example 9 may include or use, or may optionally be combined with the subject matter of at least one of Examples 1-8 to include or use, wherein the first and second pairs of differential signal lines are configured in a Ball Grid Array (BGA) pinout pattern.

Example 10 may include or use, or may optionally be combined with the subject matter of at least one of Examples 1-2 to include or use a third pair of differential signal lines including a fifth signal line electrically coupled to the first signal line and a sixth signal line electrically coupled to the second signal line, wherein the fifth and sixth signal lines are separated from each other along a line parallel to the first line.

Example 11 may include or use, or may optionally be combined with the subject matter of at least one of Examples 1-10 to include or use, wherein the first pair of differential signal lines are first and second vias.

Example 12 may include or use, or may optionally be combined with the subject matter of at least one of Examples 1-10 to include or use, wherein the first pair of differential signal lines are first and second solder pads.

Example 13 may include or use subject matter (such as an apparatus, a method, a means for performing acts, or a device readable memory including instructions that, when performed by the device, may cause the device to perform acts), such as may include or use a PCB comprising a first plurality of pairs of differential signal solder pads, wherein each pair of differential signal solder pads of the first plurality of differential signal solder pads includes a first pad separated from a second pad along a respective line connecting the centroids of the first and second pads, wherein the lines of the first plurality of pairs of differential signal solder pads are generally parallel to each other, and a second plurality of pairs of differential signal solder pads, wherein each pair of differential signal solder pads of the second plurality of differential signal solder pads includes a third pad separated from a fourth pad along a respective line connecting the centroids of respective third and fourth solder pads, wherein the lines of the second plurality of pairs of differential signal solder pads are generally parallel to each other and generally perpendicular to the lines of the first plurality of pairs of differential signal solder pads.

Example 14 may include or use, or may optionally be combined with the subject matter of Example 12 to include or use, a first plurality of pairs of differential signal vias, wherein each pair of differential signal vias of the first plurality of differential signal vias includes a first via electrically coupled to a respective first pad of the first plurality of pairs of differential signal solder pads and a second via electrically coupled to a respective second pad of the first plurality of pairs of differential signal solder pads, the first via separated from the second via along a respective line connecting the centroids of the first and second vias, wherein the lines of the first plurality of pairs of differential signal vias are generally parallel to each other and the lines of the first plurality of pairs of differential signal solder pads.

Example 15 may include or use, or may optionally be combined with the subject matter of Example 14 to include or use a second plurality of pairs of differential signal vias, wherein each pair of differential signal vias of the second plurality of differential signal vias includes a third via electrically coupled to a respective third pad of the second plurality of pairs of differential signal solder pads and a fourth via electrically coupled to a respective fourth pad of the second plurality of pairs of differential signal solder pads, the third via separated from the fourth via along a respective line connecting the centroids of the third and fourth vias, wherein the lines of the second plurality of pairs of differential signal vias are generally parallel to each other and the lines of the second plurality of pairs of differential signal solder pads, and perpendicular to the lines of the first plurality of pairs of differential signal solder pads.

Example 16 may include or use, or may optionally be combined with the subject matter of at least one of Examples 13-15 to include or use, wherein the first plurality of pairs of differential signal solder pads are on a first layer of the PCB and wherein the PCB includes a second layer including a ground plane.

Example 17 may include or use subject matter (such as an apparatus, a method, a means for performing acts, or a device readable memory including instructions that, when performed by the device, may cause the device to perform acts), such as may include or use a printed circuit board (PCB) including a first pair of differential signal solder pads comprising a first solder pad and a second solder pad proximate the first solder pad, the first solder pad and the second solder pad separated from each other along a first line and a second pair of differential signal solder pads comprising a third solder pad proximate a fourth solder pad, the third solder pad and the fourth solder pad separated from each other along a second line generally perpendicular to the first line, and a package including a differential signal pinout electrically connected to the first pair of differential signal solder pads and the second pair of differential signal solder pads.

Example 18 may include or use, or may optionally be combined with the subject matter of Example 17 to include or use, wherein the PCB further includes a third pair of differential signal solder pads comprising a fifth solder pad proximate a sixth solder pad, the fifth solder pad and the sixth solder pad separated from each other along a third line generally parallel to the first line and generally perpendicular to the second line, and the pinout of the package is electrically connected to the third pair of differential signal solder pads.

Example 19 may include or use, or may optionally be combined with the subject matter of Example 18 to include or use, wherein the PCB further includes a fourth pair of differential signal solder pads comprising a seventh solder pad proximate an eighth solder pad, the seventh solder pad and the eighth solder pad separated from each other along a fourth line generally perpendicular to the first line, generally parallel to the second line, and generally perpendicular to the third line, and the pinout of the package is electrically connected to the third pair of differential signal solder pads.

Example 20 may include or use, or may optionally be combined with the subject matter of Example 17 to include or use, wherein the PCB further includes a pair of differential signal vias including a first via and a second via, wherein the first and second vias are separated from each other along a line parallel to the first line and wherein the first via is electrically coupled to the first solder pad and the second via is electrically coupled to the second solder pad.

As used herein, a “-” (dash) used when referring to a reference number means “or”, in the non-exclusive sense discussed in the previous paragraph, of all elements within the range indicated by the dash. For example,103A-B means a nonexclusive “or” of the elements in the range {103A,103B}, such that103A-103B includes “103A but not103B”, “103B but not103A”, and “103A and103B”.