Abstract:
A contact pin for a connector. The contact pin is broken into first and second pin parts. An equalization component is directly and serially attached between the first and second pin parts, and no equalization components are mounted to a printed circuit board.

Description:
RELATED APPLICATIONS  
       [0001]     This application claims the benefit of U.S. provisional application 60/703,816, filed on Jul. 28, 2005. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to equalization in contacts, and in particular relates to a passive equalization component connected directly and serially to a contact pin of a connector.  
         [0004]     2. Description of Related Art  
         [0005]     High speed cables today implement passive and active (silicon based) equalization circuits in their connectors to modify the characteristics of the signal to either travel farther (i.e. use longer cables) or transmit faster (i.e. at a higher data rate). The equalization circuit is typically made of various combinations of resistors, capacitors and/or inductors. All known art involves the use of an intermediary circuit board, on which the equalization circuit components are mounted, that is attached to a cable connector on one side and the cable on the other side. US 2005/0112920, which discloses equalization components mounted on a circuit board and connected in parallel across the contacts, is indicative of the state of the art.  
         [0006]     An exemplary prior art equalization circuit configuration is depicted in  FIG. 1 . Equalization components or circuit  10  are mounted on printed circuit board  12 . Circuit board  12  is mounted between connector  14  and cable  16 . Pins  18  from connector  14  attach to circuit board  12 , and wires  20  from cable  16  attach to circuit board  12 . An over molding  22  will typically be formed around the connector-cable interface.  
         [0007]     Today&#39;s protocols (data transmission schemes) call for both physical (connector type, cable type and maximum length) and logical (minimum/maximum data rates, encoding schemes, etc.) layers. However, physical properties of the conductors (wires and pins) as well as the dielectric medium surrounding the conductors cause a tradeoff in the maximum data rate allowable to the distance that the signal can be transmitted. This proportionality is an inverse function: as the data rate increases the permissible transmission distance decreases. Conversely, a slower signal can be sent farther.  
         [0008]     Ideally, the signal path impedance should be matched to the output impedance of the driver and the input impedance of the receiver. In reality, however, numerous impedance mismatches are introduced along the path.  
         [0009]     The present invention overcomes these disadvantages of the prior art, and allows a signal to be sent both faster and farther.  
       SUMMARY OF THE INVENTION  
       [0010]     A contact pin for a connector according to the present invention comprises first and second pin portions, and an equalization component directly and serially attached between the first and second pin portions. In one embodiment, the equalization component comprises passive devices such as resistors and inductors that are soldered between the pin portions. The equalization component is not mounted to a printed circuit board.  
         [0011]     In one embodiment, a cable connector is connected to the first pin portion and a cable wire is connected to the second pin portion, and the connector-pin-equalization-pin-wire signal path is co-linear. Preferably, the pin is removable from the cable wire.  
         [0012]     The pins can be placed variably in a multi-pin configuration to optimize electrical characteristics. Equalization is applied on a pin-by-pin basis.  
         [0013]     The present invention also provides a method for forming a connector having a contact pin with an in-line equalization component A contact pin is broken into two parts. A contact pin is then directly connected between the two parts, such as by soldering, without an intermediate component such as a circuit board.  
         [0014]     Other features, advantages and embodiments of the invention will be apparent from the following detailed description, drawings and claims. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]      FIG. 1  is a prior art circuit configuration.  
         [0016]      FIG. 2  is a cable-connector interface according to the present invention.  
         [0017]     FIGS.  3 A-C are exemplary schematics of passive equalization circuits.  
         [0018]     FIGS.  4 A-B depict a connector according to the present invention.  
         [0019]     FIGS.  5 A-B depict exemplary circular pin layouts according to the present invention.  
         [0020]     FIGS.  6 A-B depict exemplary rectangular pin layouts according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]      FIG. 2  depicts a cable-connector interface with passive equalization according to the present invention. Equalization components  50  are attached directly to pins  52 . This approach provides for better performance as well as a more reliable assembly since fewer components are involved.  
         [0022]     Equalization components  50  are directly connected to and added in-line (serially) with signal pin  52 . Components  50  are directly connected to pin  52 , without a printed circuit board mounting or any other sort of transition region. Equalization components  50  comprise a combination of passive components, typically a resistor or capacitor. Many combinations of passive components are suitable. Exemplary schematic representations of suitable equalization circuits are illustrated in FIGS.  3 A-C.  FIG. 3A  depicts an R-C (resistor-capacitor) filter  60 .  FIG. 3B  depicts a C-R-C filter  62 .  FIG. 3C  depicts an L-R-C filter  64 . Many other combinations of passive components are possible and within the scope of this invention.  
         [0023]     In order to configure equalization components  50  in-line with pin  52 , in one embodiment, pin  52  is broken and then electrically connected to the combination of components.  FIG. 4A  depicts a standard pin  70  secured within a pin retainer  72  and encased within a connector shell  74 . In  FIG. 4B , pin  70  is broken into a front end  76  and a rear end  78 . Equalization components  80  are then directly, coaxially and linearly connected between front end  76  and rear end  78 . Equalization components  80  may comprise, for example, a chip resistor  82  in parallel with a chip capacitor  84 . Although in parallel with each other, chip resistor  82  and capacitor  84  are directly connected coaxially with pin  70  (i.e., with each of front end  76  and rear end  78 ), and are linearly in the path of a signal traveling through pin  70 .  
         [0024]     Pin  70  is preferably removable from and insertable into its connection to the signal wire (i.e pin retainer  72 ). This facilitates repair and allows for easy interchange of the pin/contact if the equalization needs to be changed. This is a significant advantage over the prior art, where pins are not removable and any change or repair necessitates substantial re-wiring.  
         [0025]      FIGS. 4A and 4B  depict a coaxial contact used for single ended signaling. However, it should be understood that the present invention provides variable pin (contact) placement capability, and that equalized pins may be placed in any layout configuration that is desired. Pins can be sized and spaced to optimize electrical characteristics including capacitance, inductance, impedance, pin-to-pin coupling, pin-to-shell coupling and crosstalk. Equalized pins can also be arranged in optimal individual modules that are then inserted into inserts that are plated to provide grounding/shielding between the modules. A plated, removable backshell is also provided, and the connector is environmentally sealed.  
         [0026]     FIGS.  5 A-B and  6 A-B illustrate several equalized pin layouts. It should be understood that that these are merely exemplary layouts, and that many other layouts are possible and within the scope of this invention.  FIG. 5A  shows a single multi-pin module  90  having multiple, equalized pins  92 . Equalization is applied on a pin-by-pin basis. Thus, all or some of pins  92  would have in-line equalization components formed as discussed with reference to FIGS.  4 A-B.  FIG. 5B  shows a four multi-pin module insert  94 , having four multi-pin modules  92 , each of which again having some or all of its pins  92  with in-line equalization.  FIG. 6A  shows a single rectangular connector  96  with multiple, equalized pins  98 .  FIG. 6B  depicts a rectangular connector  99  with six rectangular multi-pin modules  96 .  
         [0027]     Direct connection of the equalization components to the pins of the connector allows for a very closely matched impedance path for signals coming into and going out of the connector. By manipulating the spacing of the pins, and the dielectric constant of the equalization component composite material, the correct impedance of the receiver/driver can be maintained right up to the leads of the IC. Accurate control of the pin impedance also allows signals to be regenerated, repeated and retimed more accurately, and to be driven farther and faster. A connector with an in-line serial equalization component is simply added inline to allow regeneration of the signal at an appropriate data rate, thereby extending the distance.  
         [0028]     Preferably, the wire-contact-equalization-contact attachments are all co-linear axially to provide even greater impedance maintenance. This is in contrast to a configuration such as that disclosed in US 2005/0112920, for example, where signal wires must be bent to be placed along the contacts. Such a non-linear geometry introduces greater impedance into the signal path.  
         [0029]     Modification to the particular embodiments of the invention described herein may be made without departing from the spirit and scope of the invention. The described embodiments are illustrative and not restrictive, and the scope of the invention is indicated by the appended claims, rather than the foregoing description. All modifications which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.