PATENT DOCUMENT

Publication Number: US-9698535-B2
Application Number: US-201514706997-A
Country: US
Kind Code: B2

Title: Connector system impedance matching

Abstract:
Connector inserts and receptacles that provide signal paths having desired impedance characteristics. One example may provide a connector system having a connector insert and a connector receptacle. Contacts in the connector insert may form signal paths with corresponding contacts in the connector receptacle. Additional traces in the connector insert and receptacle may be part of these signal paths. The signal paths may have a target or a desired impedance along their lengths such that the power paths electrically appear as transmission lines. Constraints on physical dimensions of the connector insert and connector receptacle contacts may result in variations in impedance along the signal paths. Accordingly, embodiments of the present invention may provide structures to reduce these variations, to compensate for these variations, or a combination thereof.

Claims:
What is claimed is: 
     
       1. A connector system comprising:
 a connector insert having a first contact; and 
 a connector receptacle comprising:
 a second contact; and 
 a first trace on a tongue, the first trace coupled to the second contact, 
 
 wherein the first contact engages the second contact, and wherein the first contact, the second contact, and the first trace form a signal path when the connector insert is inserted in the connector receptacle, and 
 wherein the signal path has an average impedance along its length, the impedance of the signal path at the second contact is lower than the average impedance, and the impedance of the signal path along a portion of the first trace is higher than the average impedance, wherein the average impedance, the impedance of the signal path at the second contact, and the impedance of the signal path along a portion of the first trace are impedances at a frequency of data signals conveyed by the signal path. 
 
     
     
       2. The connector system of  claim 1  wherein the impedance of the signal path along the first trace is varied such that a filter to reduce the common-mode energy of signals conveyed on the signal path is formed. 
     
     
       3. The connector system of  claim 1  wherein the connector insert further comprises a housing, the housing having a central ground plane. 
     
     
       4. The connector system of  claim 3  wherein a first portion of the first contact is over the central ground plane and the impedance of the signal path between the first portion of the first contact and the tongue is higher than the average impedance. 
     
     
       5. The connector system of  claim 1  wherein the first contact comprises a spring-finger contact. 
     
     
       6. The connector system of  claim 5  wherein the second contact is a surface contact on the tongue of the receptacle. 
     
     
       7. The connector system of  claim 1  wherein when the connector insert is inserted into the connector receptacle, spring finger contacts in the insert contact surface contacts on the tongue in the receptacle. 
     
     
       8. The connector system of  claim 7  wherein the tongue is formed of a multi-layer printed circuit board. 
     
     
       9. The connector system of  claim 8  wherein the surface contacts are printed on top and bottom sides of the multi-layer printed circuit board. 
     
     
       10. The connector system of  claim 9  further comprising a ground plane on a layer at least near a center of the multi-layer printed circuit board, wherein a portion of the ground plane is thinned below the first contact. 
     
     
       11. The connector system of  claim 10  further comprising a power plane on a first layer at least near a center of the multi-layer printed circuit board, a first ground plane on a second layer above the power plane and a second ground plane on a third layer below the power plane, wherein a portion of the first ground plane is either thinned or open below the first contact. 
     
     
       12. The connector system of  claim 1  wherein the average impedance of the signal path at a frequency of data signals conveyed by the signal path is a function of inductances and capacitances of the signal path, the impedance of the signal path at the second contact at a frequency of data signals conveyed by the signal path is a function of inductances and capacitances of the second contact, and wherein the impedance of the signal path along a portion of the first trace at a frequency of data signals conveyed by the signal path is a function of the inductances and capacitances of the signal path along the portion of the first trace. 
     
     
       13. A connector receptacle comprising:
 a first contact; and 
 a first trace on a tongue, the first trace coupled to the first contact, 
 wherein first contact and first trace form a signal path, and 
 wherein the signal path has an average impedance along its length, the impedance of the signal path at the first contact is lower than the average impedance, and the impedance of the signal path along a portion of the first trace is higher than the average impedance, wherein the average impedance, the impedance of the signal path at the first contact, and the impedance of the signal path along a portion of the first trace are impedances at a frequency of data signals conveyed by the signal path. 
 
     
     
       14. The connector receptacle of  claim 13  wherein the impedance of the signal path along the first trace is varied such that a filter to reduce the common-mode energy of signals conveyed on the signal path is formed. 
     
     
       15. The connector receptacle of  claim 13  wherein the first contact is one of a plurality of surface contact contacts on the tongue of the receptacle. 
     
     
       16. The connector receptacle of  claim 15  wherein the tongue is formed of a multi-layer printed circuit board. 
     
     
       17. The connector receptacle of  claim 16  wherein the plurality of surface contacts are printed on top and bottom sides of the multi-layer printed circuit board. 
     
     
       18. The connector receptacle of  claim 17  further comprising a ground plane on a layer at least near a center of the multi-layer printed circuit board, wherein a portion of the ground plane is thinned below the first contact. 
     
     
       19. The connector receptacle of  claim 18  further comprising a power plane on a first layer at least near a center of the multi-layer printed circuit board, a first ground plane on a second layer above the power plane and a second ground plane on a third layer below the power plane, wherein a portion of the first ground plane is either thinned or open below the first contact. 
     
     
       20. The connector receptacle of  claim 19  wherein a high capacitance dielectric having a relative permittivity greater than 500 is located between the first ground plane and the power plane, and between the power plane and the second ground plane. 
     
     
       21. The connector receptacle of  claim 13  wherein the average impedance of the signal path at a frequency of data signals conveyed by the signal path is a function of inductances and capacitances of the signal path, the impedance of the signal path at the first contact at a frequency of data signals conveyed by the signal path is a function of inductances and capacitances of the first contact, and wherein the impedance of the signal path along a portion of the first trace at a frequency of data signals conveyed by the signal path is a function of the inductances and capacitances of the signal path along the portion of the first trace.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims the benefit of U.S. provisional application No. 61/990,700, filed May 8, 2014, and 62/004,834, filed May 29, 2014, which are incorporated by reference. 
    
    
     BACKGROUND 
     The amount of data transferred between electronic devices has grown tremendously the last several years. Large amounts of audio, streaming video, text, and other types of information content are now regularly transferred among desktop and portable computers, media devices, handheld media devices, displays, storage devices, and other types of electronic devices. 
     Data may be conveyed over cables that may include wire conductors, fiber optic cables, or some combination of these or other conductors. Cable assemblies may include a connector insert at each end of a cable, though other cable assemblies may be connected or tethered to an electronic device in a dedicated manner. The connector inserts may be inserted into receptacles in the communicating electronic devices to form pathways for data and power. 
     These connector inserts may include contacts or pins that form signal paths with contacts or pins in the corresponding connector receptacles. It may be desirable that these signal paths have a matched impedance over their lengths in order to increase the data rate that the signal path can support. That is, it may be desirable that these signal paths appear as transmission lines having a specific impedance. These transmission lines may convey signals that are substantially free of reflections, rise and fall time distortions, and other artifacts that may slow data transfers. Such transmission lines may be capable of handling higher data transmission rates than a signal path that does not have a matched impedance. This may be particularly important for large data transfers. 
     New generations of electronic devices are consistently becoming thinner and smaller. This reduction in device thickness has led to connector systems having a reduced height. This results in individual connector system components becoming thinner as well. Unfortunately, as these components become thinner, it may become harder to maintain the desired impedance along these signal paths. 
     Thus, what is needed are connector inserts and receptacles that provide signal paths having desired impedance characteristics. 
     SUMMARY 
     Accordingly, embodiments of the present invention may provide connector inserts and receptacles that provide signal paths having desired impedance characteristics. An illustrative embodiment of the present invention may provide a connector system having a connector insert and a connector receptacle. Contacts in the connector insert may form electrical paths with corresponding contacts in the connector receptacle. These electrical paths may be used as signal paths, power paths, or other types of electrical paths, but may be referred to here as signal paths for simplicity. Additional traces in the connector insert and receptacle may be part of these signal and power paths. 
     The signal paths may have a target or desired impedance along their lengths such that the signal paths electrically appear as transmission lines. Constraints on physical dimensions of the connector insert and connector receptacle contacts may result in variations in impedance along the signal paths. Accordingly, embodiments of the present invention may provide structures to reduce these variations in impedance. Other embodiments of the present invention may provide structures to compensate for these variations, or structures may be provided to reduce and compensate for these variations in impedance. It should be noted that the impedances described here are impedances at a frequency, for example, the signal frequency or a frequency component of signals conveyed by these signal paths. 
     In one illustrative embodiment of the present invention, a connector insert may include spring finger contacts. These contacts may engage corresponding surface contacts on a connector receptacle tongue when the connector insert is inserted into the connector receptacle. Traces in or on the tongue may be used to route signals to and from the connector receptacle contacts. Signal paths in this connector system may include the spring finger contacts in the connector insert and the contacts and traces in and on the tongue of the connector receptacle. 
     These signal path impedances may have various errors or fluctuations along their lengths. For example, a contact in the connector insert may be located above or below a ground plane, where the ground plane is located along a center line of the connector insert. The contact may have a capacitance to the ground plane, where the capacitance increases with the proximity of the contact to the ground plane. Since impedance is inversely proportional to the square root of the capacitance, when the contact is closer to the ground plane, the impedance may decrease. Keeping the spacing between the contact and ground plane relatively constant may allow the impedance to be well controlled along the contact&#39;s length, but there may be a discontinuity where the insert contacts extend beyond the ground plane and housing. The nearest ground or fixed potential may be further away at this point, leading to an increase in impedance in the signal path at that point. Conversely, the size of receptacle contacts needed to provide a wiping function and to reliable engage the insert contacts may lead to an increase in capacitance and a resulting decrease in impedance at that point. Also, excess portions of the connector insert and receptacle contacts may create stubs, which may act as capacitors, thereby further reducing the impedance at the connector receptacle contact. 
     Illustrative embodiments of the present invention may reduce or at least partially compensate for these and other impedance errors. In one example, the ground plane in the connector insert may extend such that it engages or contacts a corresponding ground plane in a connector receptacle. In this way, the connector insert contacts do not extend beyond this combined ground plane and the discontinuity that would otherwise result may be avoided. 
     In these and other embodiments of the present invention, the decrease in impedance near the connector receptacle surface contacts may be reduced. For example, signal contacts having a reduced depth may be provided. These reduced depth contacts may have an increased distance to a center ground plane in the tongue. The increased distance may reduce coupling capacitance, thereby increasing local impedance. In this and other embodiments, power contacts may be deeper or thicker to provide an increase in current handling capability. 
     In other illustrative embodiments of the present invention, the ground plane may be thinned below the signal contacts to further increase a distance between a signal contact and the ground plane. In still other illustrative embodiments of the present invention, the ground plane may have openings below the signal contacts. While this may allow cross-talk between signal contacts on a top and bottom of the connector receptacle tongue, the impedance error may be reduced enough to provide an overall improvement in performance. In these and other embodiments, the traces may be offset from each other to reduce this crosstalk. 
     In this and other embodiments of the present invention, a ground plane may reside near a center of the tongue. In other embodiments of the present invention, the central plane may be a power plane. Other planes may be located above or below these central planes. Again, these may be power or ground planes. For example, a power plane may be centrally located and ground planes may be positioned above and below the central plane. A high capacitance dielectric may be placed between the power and ground planes in order to form bypass capacitors between power and ground. This capacitance may help to reduce the return path impedance and may help to reduce power supply noise. For example, a dielectric having a dielectric constant or relative permittivity on the order of 100 to 1,000 or higher may be used. 
     In the above embodiments of the present invention, impedance errors may be reduced. In these and other embodiments of the present invention, the above impedance errors may be compensated for. For example, traces connected to contacts on the connector receptacle tongue may be arranged to provide higher or lower impedances than the desired impedance of the signal paths in order to compensate for the above, and other, impedance errors. In an illustrative embodiment of the present invention, a distance between these traces and a ground plane may be varied, for example from tens of microns to hundreds of microns, in order to adjust the impedance of a portion of a trace in a tongue. This impedance may be set such that the average or effective impedance for the overall signal trace meets a desired specification or target. 
     In still other embodiments of the present invention, the arrangement of these traces may be varied to construct a distributed element filter. For example, the width of traces in a signal pair, a distance or spacing between traces in a signal pair, as well as distances between these traces and a ground plane may be varied in a receptacle tongue. Also, a material that the tongue or other connector portions are made of may be varied or removed in order to change a dielectric constant or permittivity between or among traces, contacts, ground planes, and other structures. These variations may result in different common-mode impedances for the signal path pair along various sections of the traces. In various embodiments of the present invention, differential-mode impedances may remain at least approximately constant among multiple of these sections. These sections having different common-mode impedances may be arranged to form a common-mode filter to filter or reduce common-mode energy in signals conveyed along the signal path. That is, the signal path pair may be used to convey a differential signal, and the variance of the common-mode impedance may be used to form an in-line filter to remove common-mode energy from the differential signal pair. For example, a choke, notch, low-pass, high-pass, band-pass, or other type filter may be formed. These and similar techniques may be used to filter power supplies as well, for example by forming a common-mode low-pass or choke filter. 
     Again, in illustrative embodiments of the present invention, parameters and dimensions of traces and other structures on a tongue may be varied to change impedances. These impedances may include a single-ended impedance, which may be the impedance of a contact or trace to ground. These impedances may also include a common-mode impedance, which may be the impedance between a pair of contacts and traces to ground, and a differential-mode impedance, which may be the impedance between a pair of contacts or traces to each other. 
     These impedances may be varied in several ways in embodiments of the present invention. For example, traces may be made wider, narrower, thicker, thinner, closer to each other, and farther apart. They may be thinned or thickened. The dielectric between them may be varied. Holes may be formed in the dielectric or conductive material and structures. 
     These different techniques may be employed by various embodiments of the present invention to accomplish various goals. For example, in small connectors, the small geometries may result in large capacitances between a signal trace or contact and ground. This may result in a low impedance to ground at the signal frequencies. These various techniques may be used by embodiments of the present invention to increase signal path impedance to ground. Also, common-mode and differential-mode impedances may be varied among different sections of traces or interconnect in a connector. These impedances may be arranged to form distributed element filters along these traces. 
     Again, these different techniques may be used to increase or otherwise adjust an impedance of a signal path. In an illustrative embodiment of the present invention, a pair of traces may be formed on a plastic tongue. Material may be removed from sections of the area between the traces on the tongue. This may act to decrease the dielectric constant or permittivity between the traces in these sections, thereby increasing the impedance. In another illustrative embodiment of the present invention, this material may be removed from an area between contacts or traces and a center ground plate of the connector. Again, this may act to decrease the dielectric constant or permittivity between the traces in these sections, thereby increasing the impedance. This material may be removed in relatively large sections. In other embodiments of the present invention, micro-perforations or other sized perforations, in either or both the material between the traces and a ground plane or in the ground plane itself, may be used to increase impedance. In these and other embodiments of the present invention, these perforations may be formed on the contacts themselves. These perforations may form a photonic bandgap, which may also be used as a filter element. In other embodiments of the present invention, one or more sections of a center ground plane may have a raised or lowered section below one or more contacts to lower or raise an impedance at the contact. 
     Again, common-mode and differential-mode impedances may be varied among different sections of traces or interconnect in a connector. These impedances may be arranged to form distributed element filters along these traces. Other structures, such as open ended or shorted stubs may be included in these filters. In an illustrative embodiment of the present invention, traces may be arranged such that a common-mode impedance may be varied among different sections of a pair of the traces. This may be used to form a common-mode filter that may block common-mode currents and reduce electro-magnetic interference. The traces may also be arranged such that a differential-mode impedance may be held relatively constant among the sections. Accordingly, this filter may provide limited differential filtering and may have only a limited effect on a differential signal conveyed on the traces. In this way, common-mode impedances may be varied along a trace, while a differential-mode impedance may remain relatively constant along the trace. These sections may be arranged using distributed element filter and transmission filter techniques to form filters to block common-mode signals while allowing differential-mode signals pass. 
     While embodiments of the present invention may be used with connector systems having spring finger contacts in the insert and surface contacts on a tongue in the receptacle, other embodiments of the present invention may provide connector systems where the receptacle includes spring finger contacts and the insert includes a tongue supporting a number of contacts. In still other embodiments, a tongue may be in either, both, or neither the insert and receptacle, and various types of contacts may be employed in the insert and receptacle. 
     The connector receptacle tongues employed by embodiments of the present invention may be formed in various ways of various materials. For example, the tongue may be formed using a printed circuit board. The printed circuit board may include various layers having traces or planes on them, where the various traces and planes are connected using vias between layers. The printed circuit board may be formed as part of a larger printed circuit board that may form a logic or motherboard in an electronic device. In other embodiments of the present invention, these tongues may be formed of conductive or metallic traces and planes in or on a nonconductive body. The nonconductive body may be formed of plastic or other materials. 
     In various embodiments of the present invention, contacts, ground planes, traces, and other conductive portions of connector inserts and receptacles may be formed by stamping, metal-injection molding, machining, micro-machining, 3-D printing, or other manufacturing process. The conductive portions may be formed of stainless steel, steel, copper, copper titanium, phosphor bronze, or other material or combination of materials. They may be plated or coated with nickel, gold, or other material. The nonconductive portions may be formed using injection or other molding, 3-D printing, machining, or other manufacturing process. The nonconductive portions may be formed of silicon or silicone, rubber, hard rubber, plastic, nylon, liquid-crystal polymers (LCPs), or other nonconductive material or combination of materials. The printed circuit boards used may be formed of FR-4, BT or other material. Printed circuit boards may be replaced by other substrates, such as flexible circuit boards, in many embodiments of the present invention. 
     Embodiments of the present invention may provide connectors that may be located in, and may connect to, various types of devices, such as portable computing devices, tablet computers, desktop computers, laptops, all-in-one computers, wearable computing devices, cell phones, smart phones, media phones, storage devices, portable media players, navigation systems, monitors, power supplies, adapters, remote control devices, chargers, and other devices. These connectors may provide pathways for signals that are compliant with various standards such as Universal Serial Bus (USB) including USB-C, High-Definition Multimedia Interface® (HDMI), Digital Visual Interface (DVI), Ethernet, DisplayPort, Thunderbolt™, Lightning™, Joint Test Action Group (JTAG), test-access-port (TAP), Directed Automated Random Testing (DART), universal asynchronous receiver/transmitters (UARTs), clock signals, power signals, and other types of standard, non-standard, and proprietary interfaces and combinations thereof that have been developed, are being developed, or will be developed in the future. Other embodiments of the present invention may provide connectors that may be used to provide a reduced set of functions for one or more of these standards. In various embodiments of the present invention, these interconnect paths provided by these connectors may be used to convey power, ground, signals, test points, and other voltage, current, data, or other information. 
     Various embodiments of the present invention may incorporate one or more of these and the other features described herein. A better understanding of the nature and advantages of the present invention may be gained by reference to the following detailed description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a connector system according to an embodiment of the present invention; 
         FIG. 2  illustrates a transmission line model for a signal path in the connector system of  FIG. 1 ; 
         FIG. 3  illustrates an example of the variation in impedance along a signal path for the connector system of  FIG. 1 ; 
         FIG. 4  illustrates a front cross-section view of a connector receptacle tongue according to an embodiment of the present invention; 
         FIG. 5  illustrates another front cross-section view of a connector receptacle tongue according to an embodiment of the present invention; 
         FIG. 6  illustrates another front cross-section view of a connector receptacle tongue according to an embodiment of the present invention; 
         FIG. 7  illustrates another front cross-section view of a computer receptacle tongue according to an embodiment of the present invention; 
         FIG. 8  illustrates another front view cross-section of a computer receptacle tongue according to an embodiment of the present invention; 
         FIG. 9  illustrates another front view cross-section of a computer receptacle tongue according to an embodiment of the present invention; 
         FIG. 10  illustrates another connector system according to an embodiment of the present invention; 
         FIG. 11  illustrates another connector system according to an embodiment of the present invention; 
         FIG. 12A  illustrates a spectrum of a signal passing through signal path according to an embodiment of the present invention; 
         FIG. 12B  illustrates a differential signal path having a high common-mode impedance according to an embodiment of the present invention; 
         FIG. 12C  illustrates a differential signal path having a low common-mode impedance according to an embodiment of the present invention; 
         FIG. 13  illustrates a portion of a top surface of a connector tongue according to an embodiment of the present invention; 
         FIG. 14  illustrates a cutaway view of the tongue section of  FIG. 13 ; 
         FIG. 15  illustrates a top of a connector tongue according to an embodiment of the present invention; 
         FIG. 16  illustrates a cross section of a connector tongue according to an embodiment of the present invention; 
         FIG. 17  illustrates a top view of a portion of a connector tongue according to an embodiment of the present invention; 
         FIG. 18  illustrates a top view of a portion of a connector tongue according to an embodiment of the present invention; 
         FIG. 19  illustrates a top view of a portion of a tongue according to an embodiment of the present invention; 
         FIG. 20  illustrates a top view of a portion of a connector tongue according to an embodiment of the present invention; and 
         FIG. 21  illustrates another top view of a portion of a connector tongue according to an embodiment of the present invention. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       FIG. 1  illustrates a connector system according to an embodiment of the present invention. This figure, as with the other included figures, is shown for illustrative purposes and does not limit either the possible embodiments of the present invention or the claims. 
     In connector system  100 , a portion of a connector insert has been inserted into a connector receptacle. Shown are connector insert contacts  110  supported by connector insert housing  120 . Connector insert contacts  110  may electrically connect to conductors in a cable (not shown.) A central ground plane  130  may be located in connector insert housing  120  and may be connected to the cable as well. The connector insert may be inserted into a connector receptacle including tongue  140 . Tongue  140  may support a number of contacts  150 . Traces  152  may electrically connect contacts  150  to circuitry inside a device housing tongue  140 . Tongue  140  may further include one or more planes  160  and  170 . Planes  160  and  170  may be power supply, ground, or other types of planes. For example, plane  170  may be a power supply plane having ground plane on a top and bottom side. 
     In this example, signals may propagate along contacts  110  until they reach contact point  112 . The signals may then propagate through contacts  150  and traces  152 . Conversely, signals may propagate in the other direction, through traces  152  to contacts  150 , through contact point  112  and through connector insert contact  110 . 
     Again, it may be desirable that this signal path have a matched impedance along its entire length. For example, it may be desirable that this signal path have a 50 ohm, 85 ohm, 110 ohm, or other specific impedance along its entire length. Unfortunately, aspects of these paths may create impedance errors, variations, or fluctuations along their lengths. These errors may cause reflections and signal distortions that may reduce the data rates that would otherwise be achievable. 
     Accordingly, embodiments of the present invention may mitigate or reduce these errors. In this way, signals may be distorted to a lesser degree such that sufficiently high data rates are still achievable. For example, impedance errors may be limited resulting in signal rising and falling edges that may be distorted to a limited degree such that high data rates are possible. These and other embodiments may compensate for, or at least somewhat cancel, these errors. In this way, signals may be distorted in ways that cancel each other out such that significantly high data rates are still achievable. For example, signal rising and falling edges may be distorted in ways the cancel each other out such that high data rates remain possible. Some of the sources of these impedance errors, as well as both reduction and cancellation strategies for them are shown in the following figures. 
       FIG. 2  illustrates a transmission line model for a signal path in the connector system of  FIG. 1 . In this example, a length of connector insert contact  110  over central ground plane  130  in the connector insert may be modeled as transmission line  210 . A spacing between connector insert contact  110  and ground plane  130  may be sufficiently large and well-controlled that transmission line  210  may have a characteristic impedance very near a desired level. 
     As connector insert contact  110  extends beyond housing  120 , it may reach an open area  180  between housing  120  and a connector insert tongue  140  in the connector receptacle. Transmission line  220  may be used to model this length. The characteristic impedance of transmission line  220  may be higher than desired since ground plane  130  may be absent below connector insert contact  110 . In this and the other examples, an impedance may be increased by increasing an inductance, decreasing a capacitance, or both. Similarly, an impedance may be decreased by decreased an inductance, increasing a capacitance, or both. 
     At point  112 , connector insert contact  110  may engage corresponding contact  150  on tongue  140  of the connector receptacle. The portion of the signal path may be modeled by transmission line  240 . Extraneous edges and portions of connector insert contact  110  and connector receptacle contact  150  may be modeled as transmission line stub portions  230  and  250 . Specifically, portion  114  of contact  110  and portions  153  and  154  of contact  150 , and others, may be modeled as transmission line stub portions  230  and  250 . These transmission lines stubs may act as capacitors to reduce the characteristic impedance along this length. 
     After reaching contact  150 , signals may be routed through traces  152 . Traces  152  may have various sections, modeled here as transmission lines  260  and  270 . 
       FIG. 3  illustrates an example of the variation in impedance along a signal path for the connector system of  FIG. 1 . Again, where connector insert contact  110  is above ground plane  130  and housing  120  of the connector insert, the characteristic impedance  310  may be very near a desired impedance level, shown here as 85 ohms. Where ground plane  130  is absent below contact  110 , the impedance  320  may rise, in this example to 95 ohms. Further along, stub portions of the contacts may reduce impedance. In this example, the resulting impedance  340  may be shown as 75 ohms. 
     The relative lengths and impedance of transmission lines  220  and  240  may determine whether the overall impedance of the signal is higher or lower than desired. In this example, the lengths and impedances are shown as causing the signal path impedance to be low. To compensate for this, the impedance  360  may be purposefully raised, for example to 95 ohms. Similarly, its length may be adjusted to provide a correct amount of increase in impedance. A remaining portion of traces  152  may be at or near the nominal impedance of 85 ohms. In this way, the total average or effective impedance of the signal path may be adjusted to the desired level. 
     In this example, the impedance  310  may correspond to the characteristic impedance of transmission line  210 , impedance  320  may correspond to the characteristic impedance of transmission  220 , the impedance  340  may correspond to the characteristic impedance of transmission line  240  and stubs  230  and  250 , the impedance  360  may correspond to the characteristic impedance of transmission line  260 , while impedance  370  may correspond to characters impedance of transmission line  270  in  FIG. 2 . 
     In this and other embodiments of the present invention, one or more connector insert contacts  110  may be ground or power contacts. Contacts  150  on tongue  140  may directly connect to one of the planes  160  or  170 , for example through a via or other interconnect structure. This direct connection may reduce the effect of transmission line components  250 ,  260 , and  270 . This may improve the impedance of the ground or power contacts. It may also reduce loop currents that may otherwise cause connector suckout. The width and length of the via may be varied to adjust an inductance of the direct connection. This inductance may be tuned to compensate for one or more of the capacitances associated with transmission lines  210 ,  220 ,  230 ,  240 , or other capacitance. That is, a peaking or gain provided by the inductor may be used to cancel or reduce a dip or attenuation caused by one or more of the capacitances associated with transmission lines  210 ,  220 ,  230 ,  240 ,  250 ,  260 ,  270 , or other capacitance. 
     Similar techniques may be used on contacts  110  that are not power or ground contacts. That is, inductances, for example formed using vias, may be inserted in the signal path on tongue  140 . These inductances may be tuned to provide a peak that cancels or reduces a dip or attenuation caused by one or more of the capacitances associated with transmission lines  210 ,  220 ,  230 ,  240 , or other capacitance. 
     In one example, spacing  180  may be increased in order to make transmission line  220  more inductive and have a higher impedance to compensate for the capacitances caused by transmission line stubs  230  and  250 . An increase in spacing  180  may cause an increase in crosstalk between contacts  110  on opposite sides of the connector insert, so there may be a limit on how big this spacing  180  may be made. 
     Again, embodiments of the present invention may reduce these various errors in order to limit signal distortions through these paths. These and other embodiments of the present invention may compensate or attempt to reduce or cancel a total error through the signal path. Examples of structures used to reduce impedance errors are shown in the following figures. 
       FIG. 4  illustrates a front cross-section view of a connector receptacle tongue according to an embodiment of the present invention. In this example, contacts or traces  410  and  416  on tongue  400  may be used for power, ground, or other low impedance path. Contacts or traces  412  and  414  may be used to convey signals, such as a differential signal. A depth of contacts or traces  412  and  414  may be reduced such that a distance  440  to ground plane  420  may be greater than a distance  420  below power or ground contact  410 . This increase in distance may raise the impedance of a signal line at contacts or traces  412  and  414 . In  FIG. 2 , this may be used to increase a characteristic impedance of transmission line  240 , while in  FIG. 3  this may be used to raise impedance  340 . Using this arrangement, these contact impedances may be increased, while power and ground contacts or traces  410  may retain a large cross-section to increase their current carrying capabilities. 
     Again, in various embodiments of the present invention, tongue  400  may be formed in various ways. For example, tongue  400  may be formed of metallic contacts, traces, and planes in a plastic or other nonconductive housing. In embodiments where the tongue is a printed circuit board, meaningful differences in contact depths may be difficult to achieve and more reliance may be placed on the other reduction and compensation techniques shown below, though the reduction techniques shown in  FIGS. 4-9  may be suitable for printed circuit board tongues as well. In the various embodiments of the present invention where the tongue may be formed of a printed circuit board, the printed circuit board may be part of a larger logic or motherboard for an electronic device. 
       FIG. 5  illustrates another front cross-section view of a connector receptacle tongue according to an embodiment of the present invention. In tongue  500 , ground plane  520  may be notched at points  522  to further increase distance  540  relative to distance  530 . As before, contacts or traces  510  and  516  may be used to convey power and ground or other low impedance paths, while contacts or traces  512  and  514  may be used to convey signals, such as a differential signal. 
       FIG. 6  illustrates another front cross-section view of a connector receptacle tongue according to an embodiment of the present invention. In this example, holes  622  have been opened in ground plane  620 . This may further increase distance  640  relative to distance  630 , thereby further reducing impedance loss. Cross talk between signal contacts or traces  612  and  613  on opposite sides of tongue  600  may be possible with this arrangement. However, it may be that an improvement in impedance is enough to warrant use of openings  622  depending on the exact embodiment of the present invention. In various embodiments of the present invention, notches or openings, such as notches  522  and opening  622  may be located at least approximately directly below contacts  612  and the ground planes  520  and  620  may have their full dimensions elsewhere. In other embodiments of the present invention, notches or openings such as these may be joined or continuous for nearby or adjacent contacts. 
     In these and other embodiments of the present invention, the crosstalk between contacts or traces  612  and  613  may be mitigated by moving one or more contacts or traces laterally such that they do not align with each other. For example, contacts or traces  632  and  633  may be offset from each other such that they do not align with each other through opening  644 . 
     Again, other embodiments of the present invention may employ more than one central power or ground plane. The above techniques may be used in these situations as well. Examples are shown in the following figures. 
       FIG. 7  illustrates another front cross-section view of a computer receptacle tongue according to an embodiment of the present invention. In this example, tongue  700  may include power plane  760  having ground planes  720  and  770  on each side. In this example, a depth of signal contacts or traces  712  and  714  are reduced as compared to power and ground contacts or traces  710  and  716  such that distance  740  is greater than distance  730 . 
     Again, a high capacitance dielectric may be placed between the power  760  and ground planes  720  and  770  in order to form bypass capacitors between power and ground. This capacitance may help to reduce the return path impedance and may help to reduce power supply noise. For example, a dielectric having a dielectric constant or relative permittivity on the order of 100 to 1,000 or higher may be used. For example, a high capacitance dielectric having a relative permittivity greater than 500 may be used. 
       FIG. 8  illustrates another front view cross-section of a computer receptacle tongue according to an embodiment of the present invention. In this example, notches  822  may be formed to further increase distance  840 . 
       FIG. 9  illustrates another front view cross-section of a computer receptacle tongue according to an embodiment of the present invention. In this example, openings  922  may be formed in ground planes  920  and  970  to further increase distance  940  as compared to distance  930 . In other embodiments of the present invention, power plane  960  may have an opening as well. Again, this may result in cross talk, though improvement in impedance matching may make it worthwhile to accept this downside. 
     The above techniques may be used to reduce impedance losses near contacts on a connector receptacle tongue. Again, the embodiments shown in  FIGS. 4-9  are particularly well-suited for use with tongues having metallic or conductive contacts, traces, and planes that are supported by tongue housings formed of plastic or other nonconductive materials, though they may be used with embodiments that employ tongues formed of printed circuit boards as well. Other embodiments of the present invention may help to prevent impedance gains that may occur at openings between a connector insert and the connector receptacle ground planes. These embodiments of the present invention may be well-suited for use with both plastic tongues and tongues formed using printed circuit boards, which again may be part of a larger logic board, motherboard, or other board in an electronic device. An example is shown in the following figure. 
       FIG. 10  illustrates another connector system according to an embodiment of the present invention. As before, connector insert contacts  1010  may engage contacts  1050  on connector receptacle tongue  1040 . Traces  1052  may electrically connect to contacts  1050 . In this example, connector insert ground plane  1030  and connector tongue ground plane  1070  may be extended such that they meet at connection point  1080 . This may prevent an increase in impedance in the signal path of this point. In  FIG. 2 , this may correspond to maintaining reducing the impedance of transmission line  220 , and in  FIG. 3 , it may result in maintaining or reducing the impedance  320 . 
     Again, the above embodiments of the present invention may reduce impedance errors in a signal path in a connector system. In these and other embodiments of the present invention, other impedance errors may be introduced in order to compensate for the above, and other, impedance errors. In this way, the average or effective impedance for a signal path may be close to a desired level. An example is shown in the following figure. 
       FIG. 11  illustrates another connector system according to an embodiment of the present invention. As before, connector insert contacts  1110  may engage contacts  1150  on connector receptacle tongue  1140 . Traces  1152  may electrically connect to contacts  1150 . Traces  1152  may have various sections or portions, shown here as sections  1154  and  1156 . The height over ground plane  1170  may vary among sections. For example, section  1154  may be spaced from ground plane  1170  by distance  1155 , while section  1156  may be spaced from ground plane  1170  by distance  1157 . Since distance  1157  is shorter than distance  1155 , section  1156  may have a lower impedance than section  1154 . These techniques may be well-suited for use in embodiments of the present invention that employ tongues formed of printed circuit boards, plastic housings, or other types of tongues. 
     This variation in impedance may be used to adjust the average or effective value of a signal path to be close to a desired value. In making this adjustment, it should be noted that signals propagating through the above signals paths may pass through the various high-impedance and low-impedance sections or zones in a short amount of time. That is, each of the various high-impedance and low-impedance sections may have a short delay associated with them. These delays may be shorter than the rise and fall times of the propagating signals. The result is that the variation in impedance may be reduced when compared to what may be calculated. That is, the effective impedance for each section may be closer to the desired impedance value. The effective impedance of each section, and the effective impedance of the signal path, may be determined using conventional methods, such as transmission-line theory. 
     For example, in  FIG. 3 , the impedances  320  and  340  may be determined. Again, for illustrative purposes, the impedance  320  is shown as 95 ohms, which is 10 ohms higher than the desired value, while the impedance  340  is shown as 75 ohms, which is 10 ohms less than the desired value of 85 ohms. However, since the delays through transmission line sections  220  (which corresponds to impedance  320 ) and  240  (which corresponds to impedance  340 ) may be short when compared to the rise and fall times of a signal propagating through them, the effective impedances of transmission lines  220  and  240  may be closer to 85 ohms than these calculated values. Again, these effective impedances, and the effective impedance of the signal path, may be determined using conventional methods, such as transmission-line theory. 
     In various embodiments of the present invention, the spacing, sizes, and arrangements of transmission line segments in a tongue may be varied to create a filter. Such a filter may remove common-mode energy from differential signal pairs and other types of signals. For example, a choke, notch, low-pass, high-pass, band-pass, or other type filter may be formed. These and similar techniques may be used to filter power supplies as well, for example by forming a common-mode low-pass or “choke” filter. An example is shown in the following figures. 
       FIG. 12A  illustrates a spectrum of a signal passing through signal path according to an embodiment of the present invention. A signal path may have a spectrum  1230  that may be plotted as an amplitude  1210  over frequency  1220 . The spectrum may have a null or low value near a Nyquist frequency. Variations in rise and fall times caused by the above impedance mismatches may create a spike  1232  near the Nyquist frequency. Common-mode and differential-mode impedances of signal paths through the tongue may be varied to form a common-mode filter to reduce the amplitude of spike  1232 . 
       FIG. 12B  illustrates a differential signal path having a high common-mode impedance according to an embodiment of the present invention. In this example, contacts  1250  may be spaced away from ground plane  1240  by a distance  1242  and away from each other by distance  1252 . When distance  1242  is relatively high, the impedance between contacts  1250  and ground plane  1240  may be high. The resulting common-mode impedance may be approximately half of the impedance between each contacts  1250  and ground plane  1240 . This transmission line portion may be combined with other transmission line portions, such as the one shown in the following figure, to achieve signal filtering. 
       FIG. 12C  illustrates a differential signal path having a low common-mode impedance according to an embodiment of the present invention. In this example, signal paths  1270  are spaced from each other by distance  1272  and are a distance  1262  above ground plane  1260 . In this example, the impedance between each signal path  1270  and ground plane  1260  may be low, resulting in the low common-mode impedance. 
     In various embodiments of the present invention, filters may be formed of these trace sections by varying distances  1252 ,  1272 ,  1242 , and  1262 , both in absolute terms and relative to each other. Similarly the thickness and width of traces  1250  and  1270 , in absolute terms and relative to each other, may be varied. The material between and among these structures may be varied to change the dielectric constant or permittivity These techniques may be well-suited for use in connector systems that employ tongues formed using printed circuit boards, tongues using metallic contacts, traces, and planes supported by a plastic or nonconductive housing, or other types of tongues. 
     Again, various techniques may be used by embodiments of the present invention to increase or otherwise vary a signal path&#39;s impedance to ground. Also, common-mode and differential-mode impedances may be varied among different sections of traces or interconnect in a connector. These impedances may be arranged to form distributed element filters along these traces. Examples are shown in the following figures. 
       FIG. 13  illustrates a portion of a top surface of a connector tongue according to an embodiment of the present invention. In this example, two traces  1310  and  1320  may be formed on a surface of a tongue, where the tongue is formed of a material  1330 . Material  1330  may be plastic or other material. Material  1330  may be removed in one or more sections  1340  from between traces  1310  and  1320 . This removal may decrease a dielectric constant or permittivity between traces  1310  and  1320  near sections  1340 . This decrease in the dielectric constant or permittivity may reduce coupling capacitance, thereby increasing the impedance between signal lines or traces  1300  and  1320 . 
     In various embodiments of the present invention, sections  1340  may be formed in various ways. For example, sections  1340  may be formed by etching, molding, micro-machining, drilling, routing, cavitation, laser etching or ablation, or by using other manufacturing techniques. 
       FIG. 14  illustrates a cutaway view of the tongue section of  FIG. 13 . This section view may be taken along cutline A-A in  FIG. 13 . Again, traces  1310  and  1320  may be formed in a tongue made of a material  1330 . Section  1340  may be formed between traces  1310  and  1320 . A center ground plane  1410  may also be included. 
     In this example, sections  1340  may form filter sections along traces  1310  and  1320 . For example, a differential impedance between traces  1310  and  1320  may vary along their length to due to these presence of sections  1340 . This may form a differential filter. In various embodiments of the present invention, these sections are short enough such that a signal may not react to their presence and may not be filtered. 
     In various embodiments of the present invention, impedances at a contact on a tongue may be varied. Examples are shown in the following figures. 
       FIG. 15  illustrates a top of a connector tongue according to an embodiment of the present invention. In this example, tongue  1500  may include two contacts, contacts  1510  and  1520 . Contacts  1510  and  1520  may form areas to be contacted by pins or contacts of a corresponding connector. Contacts  1510  and  1520  may be connected to circuitry or components through traces  1512  and  1522 . 
     In various embodiments of the present invention, it may be desirable to either increase or decrease an impedance at contacts  1510  and  1520 . It may also be desirable that these contacts form a portion of a common-mode filter. By blocking common-mode currents at these contacts, return currents may not be routed through a shield of this connector. By preventing currents from being routed on the shield, the currents do not generate a voltage at the resistance of the shield. In this way, electromagnetic interference that would otherwise be generated by the connector may be reduced. 
       FIG. 16  illustrates a cross section of a connector tongue according to an embodiment of the present invention. In this example, contacts  1510  may be separated from center ground plane  1610  by material  1620 . One or more openings  1630  may be formed in material  1620 . These openings may have a lower dielectric constant, thereby decreasing a capacitance between contacts  1510  and ground plane  1610 . This may result in a higher impedance for contact  1510 . 
     In this and other examples shown, instead of simply removing material to form sections such as  1340  and  1630 , other material having different dielectric constant may be used to form these sections. As before, sections  1630  may be formed by etching, molding, micro-machining, drilling, or by using other manufacturing techniques. 
       FIG. 17  illustrates a top view of a portion of a connector tongue according to an embodiment of the present invention. Again, tongue portion  1500  may include contacts  1510  and  1520 . Either or both the dielectric below contacts  1510  and  1520  or the center ground plane may include a number of perforations or micro-vias  1710 . Perforations  1710  may be formed using a drill, etch, micro-machining, or other techniques. These perforations may act to reduce a capacitance and increase an impedance between contacts  1510  and  1520  and ground. In various embodiments of the present invention, the use of perforations  1710  may be limited to avoid weakening the structure of tongue  1500 . 
     Again, in various embodiments of the present invention, it may be desirable to either raise or lower an impedance of a contact or trace. An example is shown in the following figure. 
       FIG. 18  illustrates a top view of a portion of a connector tongue according to an embodiment of the present invention. Again, contacts  1510  and  1520  may be located over or a tongue including central ground plane  1800 . Center ground plane  1800  may include features  1810  and  1820 . Features  1810  and  1820  may be a lowered recess, a raised mesa, or other type of feature. A lowered recess may cause a decrease in capacitance and an increase the impedance between contacts  1510  and  1520  and center ground plane  1800 . A raised mesa may increase the capacitance and decrease the impedance between contacts  1510  and  1520  and center ground plane  1800 . 
       FIG. 19  illustrates a top view of a portion of a tongue according to an embodiment of the present invention. In this example, features  1810  and  1820  have been merged into a single feature  1910 . 
     Again, common-mode and differential-mode impedances may be varied among different sections of traces or interconnect in a connector. Other structures, such as open ended or shorted stubs may be included. These impedances may be arranged to form distributed element filters along these traces. 
     In these and other embodiments of the present invention, a differential-mode impedance may be kept constant while the common-mode impedance may be varied along a pair of traces, or a differential trace. These variations in common-mode impedance along a differential trace may be arranged using distributed element filter and transmission filter techniques to form filters to block common-mode signals while allowing differential-mode signals pass. 
     In general, to vary a common-mode impedance while maintaining a differential-mode impedance between a first section of a differential trace and a second section of a differential trace, two or more parameters, such as spacing, width, thickness, dielectric constant, or other parameter, may be varied between the first and second sections. In one example, a width and a spacing may be varied such that they cancel each other in terms of differential-mode impedance, but cause a variation in common-mode impedance along the trace. An example is shown in the following figure. 
       FIG. 20  illustrates a top view of a portion of a connector tongue according to an embodiment of the present invention. In this example, two traces, or a differential trace, in section  2010  may be varied in spacing and width. In this example, along line B-B, the traces in section  2010  may be wider than the traces in section  2012  along line A-A. The traces in section  2010  may be further away from each other along line B-B than the traces in sections  2012  are along line A-A. 
     A common-mode impedance along trace section  2010  may be higher than a common-mode impedance of the section  2012 . This is because the traces are wider in section  2010  than the traces in section  2012 . This change in common-mode impedance may be enhanced by changing the materials below the traces in sections  2010  and  2012  such that they have different dielectric constants. The change in common-mode impedance may additionally be enhanced by changing a width of a trace or a center ground plane such that the distance between the two is varied between sections  2010  and  2012 . In various embodiments of the present invention, different materials having a different dielectric constant or permittivity may be used for materials  2020  and  2030 . This may be used to further change the common-mode impedance between these two sections. 
     Accordingly, the common-mode impedances between sections  2010  and  2012  may be different. However, the differential-mode impedance between traces in these sections may be a function of the width of traces in a section and a spacing or distance between the traces in a section. Accordingly, the since the traces are narrower but closer together in section  2012  while being wider but further spaced in section  2010 , the differential-mode impedances in sections  2010  and  2012  may match. 
     It should be noted that the term distances as used herein may be an electrical distance and is not limited to a purely physical distance. The electrical distance may be a function of both the physical distance and the dielectric constant or permittivity of any intervening materials. Accordingly, differences in a dielectric constant or permittivity of materials  2020  and  2030  may change the electrical distance even though the physical distance between traces in sections  2010  and  2012  does not change. 
     In this way, common-mode impedances may be varied along a trace, while a differential-mode impedance may remain relatively constant. These sections may be arranged using distributed element filter and transmission filter techniques to form filters to block common-mode signals while allowing differential-mode signals pass. 
     In the above example, a width and a spacing may be varied such that they cancel each other in terms of differential-mode impedance, but cause a variation in the common-mode impedance along the differential trace. In other embodiments of the present invention, two parameters may be varied to cancel a variation in one other parameter. For example, a change in dielectric between portions of a differential trace, a change in a width of the trace, and a change in the spacing of the trace, may be varied such that the differential-mode impendence is kept constant while the common-mode impedance is varied. An example is shown in the following figure. 
       FIG. 21  illustrates a portion of a top surface of a connector tongue according to an embodiment of the present invention. In this example, two traces having sections  2110  and  2112  may be formed on a surface of a tongue, where the tongue is formed of a material  2120 . Material  2120  may be plastic, printed circuit board, or other material. Material  2120  may be removed in one or more sections  2130  from between trace sections  2112 . This removal may decrease a dielectric constant or permittivity between trace sections  2112 . This decrease in the dielectric constant or permittivity may reduce coupling capacitance, thereby increasing the differential-mode impedance between trace sections  2112 . 
     The traces in section  2112  may also be thinner than the traces in section  2110 . This may further decrease coupling capacitance between traces in section  2112 , thereby further increasing the differential-mode impedance between trace sections  2112 . 
     To compensate for these increases, the traces in section  2112  may be closer than the traces in section  2110 . This may increase coupling capacitance between traces in section  2112 , thereby further decreasing the differential-mode impedance between trace sections  2112 . This decrease may be adjusted to compensate for the increases in differential-mode impedances caused by the traces having an opening between them and from being narrower in section  2112 . 
     While the differential-mode impedance may be constant between sections  2110  and  2112 , the common-mode impedance may vary. For example, the wider traces in section  2110  may result in a higher capacitance to a central ground plane, leading to a lower common-mode impedance as compared to the trace sections  2112 . 
     In various embodiments of the present invention, opening sections  2130  may be formed in various ways. For example, opening sections  2130  may be formed by etching, molding, micro-machining, drilling, cavitation, laser etching or ablation, or by using other manufacturing techniques. 
     In various embodiments of the present invention, contacts, ground planes, traces, and other conductive portions of connector inserts and receptacles may be formed by stamping, metal-injection molding, machining, micro-machining, 3-D printing, or other manufacturing process. The conductive portions may be formed of stainless steel, steel, copper, copper titanium, phosphor bronze, or other material or combination of materials. They may be plated or coated with nickel, gold, or other material. The nonconductive portions may be formed using injection or other molding, 3-D printing, machining, or other manufacturing process. The nonconductive portions may be formed of silicon or silicone, rubber, hard rubber, plastic, nylon, liquid-crystal polymers (LCPs), or other nonconductive material or combination of materials. The printed circuit boards used may be formed of FR-4, BT or other material. Printed circuit boards may be replaced by other substrates, such as flexible circuit boards, in many embodiments of the present invention. 
     Embodiments of the present invention may provide connectors that may be located in, and may connect to, various types of devices, such as portable computing devices, tablet computers, desktop computers, laptops, all-in-one computers, wearable computing devices, cell phones, smart phones, media phones, storage devices, portable media players, navigation systems, monitors, power supplies, adapters, remote control devices, chargers, and other devices. These connectors may provide pathways for signals that are compliant with various standards such as Universal Serial Bus (USB) including USB-C, High-Definition Multimedia Interface (HDMI), Digital Visual Interface (DVI), Ethernet, DisplayPort, Thunderbolt, Lightning, Joint Test Action Group (JTAG), test-access-port (TAP), Directed Automated Random Testing (DART), universal asynchronous receiver/transmitters (UARTs), clock signals, power signals, and other types of standard, non-standard, and proprietary interfaces and combinations thereof that have been developed, are being developed, or will be developed in the future. Other embodiments of the present invention may provide connectors that may be used to provide a reduced set of functions for one or more of these standards. In various embodiments of the present invention, these interconnect paths provided by these connectors may be used to convey power, ground, signals, test points, and other voltage, current, data, or other information. 
     The above description of embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form described, and many modifications and variations are possible in light of the teaching above. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. Thus, it will be appreciated that the invention is intended to cover all modifications and equivalents within the scope of the following claims.

Metadata:
Filing Date: 20150508
Publication Date: 20170704
Grant Date: 20170704
Priority Date: 20140508
Inventors: CORNELIUS WILLIAM
AMINI MAHMOUD R.
GAO ZHENG
Assignee: APPLE INC
CPC Classifications: [{"code": "H01R13/665", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R13/6473", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R12/721", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01R13/6469", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01R13/6473", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R12/721", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01R13/6469", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01R13/665", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 54393069