Impedance-matching electrical connection apparatus for high-speed data communications system

Abstract

This disclosure concerns systems and devices configured to implement impedance matching schemes in a high speed data transmission environment. In one example, an electrical connection system is provided that includes a circuit board upon which are disposed a one or more signal contact pads, each of which is configured to communicate with a complementary element of an external electrical device such that a respective shunt capacitance is defined. Also disposed on the circuit board are one or more inductive traces, each of which is connected to a respective contact signal pad, and each of which has an associated compensating series inductance configured to substantially offset the corresponding shunt capacitance. As well, one or more signal lines are likewise disposed on the circuit board such that each signal line is connected to a respective inductive trace. The circuit board finally includes one or more ground contact pads and power contact pads.

1 . An electrical connection system suitable for use in connection with high-frequency communication signals, the electrical connection system comprising: 
 a circuit board;    a plurality of signal contact pads disposed on the circuit board, each of the plurality of signal contact pads configured to interact with a complementary element of an electrical device such that a coupling between the signal contact pad and complementary element is defined that has an associated shunt capacitance;    a plurality of inductive traces disposed on the circuit board, each inductive trace connected to a respective contact signal pad of the plurality of signal contact pads, each inductive trace having an associated compensating series inductance configured to substantially offset a portion of the corresponding shunt capacitance; and    a plurality of signal lines disposed on the circuit board, each signal line connected to a respective inductive trace of the plurality of inductive traces.    
   
   
       2 . The electrical connection system as recited in  claim 1 , wherein the electrical connection system is compatible for use with one or more high-speed differential signal paths.  
   
   
       3 . The electrical connection system as recited in  claim 1 , wherein the electrical connection system comprises a portion of a card edge connector.  
   
   
       4 . The electrical connection system as recited in  claim 1 , wherein at least one signal contact pad defines at least one open portion through which signals cannot pass.  
   
   
       5 . The electrical connection system as recited in  claim 1 , wherein a total area defined by at least one signal contact pad includes at least one open portion through which signals cannot pass, the at least one open portion having an area in a range of at least about fifty percent to at least about seventy five percent of the total area.  
   
   
       6 . The electrical connection system of  claim 1 , wherein, for one or more predetermined data rates, each inductive trace and associated signal contact pad collectively implement an impedance that substantially matches an impedance associated with the complementary connector to which that inductive trace and signal contact pad are electrically connected.  
   
   
       7 . The electrical connection system of  claim 1 , wherein, for one or more predetermined data rates, each inductive trace and associated signal contact pad collectively implement an impedance that substantially matches an impedance of the signal line to which that inductive trace and signal contact pad are electrically connected.  
   
   
       8 . The electrical connection system of  claim 1 , wherein the compensating series inductance associated with at least one of the inductive traces is a function of a length and a width of that inductive trace.  
   
   
       9 . The electrical connection system of  claim 8 , wherein the width of the at least one inductive trace is no greater than about thirty five percent of a width of the signal line connected to the inductive trace.  
   
   
       10 . The electrical connection system of  claim 8 , wherein the width of the at least one inductive trace is no greater than about twenty five percent of a width of the signal line connected to the inductive trace.  
   
   
       11 . The electrical connection system of  claim 1 , wherein a coupling, between a contact pad and a complementary connector, cooperates with the inductive trace connected to that contact pad to collectively implement an average impedance value based in part on the offset portion of the shunt capacitance, and the average impedance value substantially matches a nominal impedance of an external transmission line of the electrical device.  
   
   
       12 . The electrical connection system of  claim 1 , further comprising at least one ground contact pad disposed on the circuit board.  
   
   
       13 . The electrical connection system of  claim 12 , further comprising a trace connected to the ground contact pad and disposed on the circuit board.  
   
   
       14 . The electrical connection system of  claim 13 , wherein the trace is configured so as to have an associated inductance that facilitates a reduction of shunt capacitance.  
   
   
       15 . The electrical connection system of  claim 1 , further comprising at least one power contact pad disposed on the circuit board.  
   
   
       16 . The electrical connection system of  claim 1 , further comprising at least one signal contact pad directly connected to a corresponding signal line and disposed on the circuit board.  
   
   
       17 . The electrical connection system of  claim 1 , further comprising a ground plane mounted on an opposite side of a dielectric layer of the circuit board from the plurality of contact pads and the plurality of inductive traces, wherein the ground plane is configured and arranged to affect a strength of a capacitive field associated with at least one of: at least one inductive trace; and, at least one signal contact pad.  
   
   
       18 . An electrical connection system suitable for use in connection with high-frequency communication signals, the electrical connection system comprising: 
 a circuit board;    a plurality of signal contact pads disposed on the circuit board, each of the plurality of signal contact pads configured to interact with a complementary element of an electrical device such that a coupling between the signal contact pad and complementary element is defined that has an associated impedance discontinuity;    a plurality of inductive traces disposed on the circuit board, each inductive trace being connected to a respective signal contact pad of the plurality of contact pads, and each inductive trace having a geometry configured to implement a reduction in the impedance continuity; and    a plurality of signal lines disposed on the circuit board, each signal line being connected to a respective inductive trace of the plurality of inductive traces.    
   
   
       19 . The electrical connection system as recited in  claim 1 , wherein the electrical connection system is compatible for use with one or more high-speed differential signal paths.  
   
   
       20 . The electrical connection system of  claim 18 , wherein each inductive trace has a width no greater than about thirty five percent of a width of the signal line connected to that inductive trace.  
   
   
       21 . The electrical connection system of  claim 18 , wherein each inductive trace has a width no greater than about twenty five percent of a width of the signal line connected to that inductive trace.  
   
   
       22 . The electrical connection system as recited in  claim 18 , wherein the electrical connection system comprises a portion of a card edge connector.  
   
   
       23 . The electrical connection system of  claim 14 , wherein each inductive trace is associated with a corresponding compensating series inductance, and the impedance discontinuity associated with each inductive trace is susceptible to reduction by use of the compensating series inductance to offset a portion of a shunt capacitance associated with the corresponding coupling.  
   
   
       24 . The electrical connection system as recited in  claim 14 , wherein at least one signal contact pad defines at least one open portion through which signals cannot pass.  
   
   
       25 . The electrical connection system as recited in  claim 14 , wherein at least one signal contact pad defines a plurality of open portions through which signals cannot pass.  
   
   
       26 . The electrical connection system of  claim 25 , wherein the plurality of open portions collectively define at least a portion of a cross-hatch pattern.  
   
   
       27 . The electrical connection system of  claim 25 , wherein plurality of open portions comprises a plurality of openings, each of which is generally in the shape of a parallelogram.  
   
   
       28 . The electrical connection system of  claim 25 , wherein the plurality of open portions collectively define at least a portion of a zigzag pattern.  
   
   
       29 . The electrical connection system of  claim 14 , further comprising at least one ground contact pad disposed on the circuit board.  
   
   
       30 . The electrical connection system of  claim 29 , further comprising a trace connected to the ground contact pad and disposed on the circuit board.  
   
   
       31 . The electrical connection system of  claim 30 , wherein the trace is configured so as to have an associated inductance that facilitates a reduction of shunt capacitance.  
   
   
       32 . The electrical connection system of  claim 14 , further comprising at least one power contact pad disposed on the circuit board.  
   
   
       33 . The electrical connection system of  claim 14 , further comprising at least one signal contact pad directly connected to a corresponding signal line.  
   
   
       34 . The electrical connection system of  claim 14 , further comprising a ground plane mounted on an opposite side of a dielectric layer of the circuit board from the plurality of contact pads and the plurality of inductive traces, wherein the ground plane is configured and arranged to affect a strength of a capacitive field associated with at least one of: at least one inductive trace; and, at least one signal contact pad.