Abstract:
Signal probing systems are provided. One such signal probing system includes: a socket configured to be electrically coupled to a processor, a printed circuit board (PCB), a separation layer that is located between the socket and the PCB, compensation circuits that each include a resistor and a capacitor coupled in parallel, and an adapter that is attached to the PCB and that is configured to be electrically coupled to a motherboard, wherein the PCB is configured to route respective probed signals through the compensation circuits, the respective probed signals being responsive to respective signals traveling between the processor and the motherboard. Methods and other systems are disclosed.

Description:
BACKGROUND  
         [0001]    One way for testing a processor is to connect the processor to a probing device that is then electrically coupled to a logic analyzer. One problem with such a probing device is that it may not be capable of accurately probing processors operating above a certain frequency (e.g., over 1 GHz). Based on the foregoing, it should be understood that there is a need for systems and methods that address this and/or other perceived shortcomings of the prior art.  
         SUMMARY  
         [0002]    An embodiment of a signal probing system includes: a socket configured to be electrically coupled to a processor, a printed circuit board (PCB), a separation layer that is located between the socket and the PCB, compensation circuits that each include a resistor and a capacitor coupled in parallel, and an adapter that is attached to the PCB and that is configured to be electrically coupled to a motherboard, wherein the PCB is configured to route respective probed signals through the compensation circuits, the respective probed signals being responsive to respective signals traveling between the processor and the motherboard.  
           [0003]    An embodiment of a method for manufacturing a signal probing system includes: attaching compensation circuits to a PCB, each of the compensation circuits including a resistor and a capacitor coupled in parallel, attaching a separation layer to the printed circuit board (PCB), the separation layer being adjacent to the compensation circuits, attaching a socket to the separation layer, the socket being configured to be electrically coupled to a processor, the socket being attached to the separation layer such that the compensation circuits are located between the socket and the PCB, attaching an adapter to the PCB, the adapter being configured to be electrically coupled to a motherboard, wherein the PCB is configured to respectively route probed signals to the compensation circuits, the probed signal being responsive to respective signals traveling between the processor and the motherboard.  
           [0004]    Other systems, methods, features and/or advantages will be or may become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features, and/or advantages be included within this description and be protected by the accompanying claims.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]    In the drawings, like reference numerals designate corresponding parts throughout the several views. Furthermore, the components in the drawings are not drawn to scale.  
         [0006]    [0006]FIG. 1 is a block diagram depicting an embodiment of a processor testing system.  
         [0007]    [0007]FIG. 2 is a block diagram depicting an embodiment of the signal probing system shown in FIG. 1.  
         [0008]    [0008]FIG. 3 is a block diagram depicting an embodiment of the processor-socket adapter shown in FIG. 2.  
         [0009]    [0009]FIG. 4 is a cross-sectional view of a portion of the processor-socket adapter shown in FIG. 3.  
         [0010]    [0010]FIG. 5 is a flow chart depicting an embodiment of a method for manufacturing a signal probing system. 
     
    
     DETAILED DESCRIPTION  
       [0011]    As will be described in more detail, a separation layer of a signal probing system separates a processor socket from a printed circuit board. This separation layer enables compensation circuits to be located closer to probing points located on respective signal paths between a processor and a motherboard. As a result, the signal probing system is capable of more accurately probing higher frequency signals traveling along such signal paths.  
         [0012]    [0012]FIG. 1 is a block diagram depicting an embodiment of a processor testing system  100 . The processor testing system  100  includes a signal probing system  101  that is coupled between a processor  102  and a motherboard  103 . The signal probing system  101  is configured to probe signals that are passed between the processor  102  and the motherboard  103  and to provide the probed signals to a testing instrument  104 . The testing instrument  104  is configured to analyze signals received from the signal probing system  101  and to provide signal analysis results to a user. The testing instrument  104  may be, for example, a logic analyzer.  
         [0013]    [0013]FIG. 2 is a block diagram depicting an embodiment of a signal probing system  101 . The signal probing system  101  includes a processor-socket adapter  201 , one or more connector boards  202 , and one or more coaxial-cable ribbons  203 . The processor-socket adapter  201  is configured to be coupled between the processor  102  and the motherboard  103  (FIG. 1). For example, the processor  102  (FIG. 1) may be plugged into the processor-socket adapter  201 , which may in turn be plugged into the motherboard  103  (FIG. 1).  
         [0014]    The connector board(s)  202  is/are configured to be coupled (directly or indirectly) to the testing instrument  104  (FIG. 1). The coaxial-cable ribbon(s)  203  is/are coupled between the processor-socket adapter  201  and respective connector board(s)  202 . When the signal probing system  101  is in operation, the processor-socket adapter  201  probes signals being passed between the processor  102  and the motherboard  103 . The coaxial-cable ribbon(s)  203  then conduct the probed signals from the processor-socket adapter  201  to respective connector board(s)  202 , which then conducts the signals to the testing instrument  104 . Alternatively, the connector board(s)  202  may conduct the signals to a signal conditioning circuit (not shown) that conditions the signals prior to providing them to the testing instrument  104 .  
         [0015]    [0015]FIG. 3 is a block diagram depicting an embodiment of a processor-socket adapter  201 . The processor-socket adapter  201  includes a processor socket  301 , a separation layer  302 , a printed circuit board (PCB)  303  and a ball-grid-array/pin-grid-array (BGA/PGA) adapter  304 . The processor socket  301  is configured to be coupled to a processor  102  (FIG. 1). For example, the pins of the processor  102  may be plugged into respective pin receptacles of the processor socket  301 . The BGA/PGA adapter  304  is configured to be plugged into a motherboard via pins  305 . The separation layer  302  and the PCB  303  conduct signals between the processor socket  301  and the BGA/PGA adapter  304 .  
         [0016]    The PCB  303  includes buried resistors (not shown in FIG. 3) that are coupled in series with respective circuits  306  (only one shown). The buried resistors and the respective circuits  306  condition respective signals that are probed by the processor-socket adapter  201 . Each compensation circuit  306  may comprise a resistor and a capacitor coupled in parallel. The PCB  303  also includes solder pads  307  (only one shown) that are configured to be soldered to respective coaxial cables corresponding to one or more respective coaxial-cable ribbons  203 .  
         [0017]    [0017]FIG. 4 is a cross-sectional view of a portion of a processor-socket adapter  201  depicting one of a plurality of respective signal paths between one of a plurality of pins  305  and one of a plurality of solder pads  307 . Similar signal paths exist between other pins  305  and other respective solder pads  307 . However, only one of such signal paths is shown in order to provide a clear and simple illustration of an exemplary embodiment.  
         [0018]    The processor socket  301  is preferably a zero-insertion-force (ZIF) socket, and the pin receptacle  314  is preferably a ZIF pin receptacle. The processor socket  301  is attached to the separation layer  302  via BGA solder balls  313  (only one ball  313  is shown). The separation layer  302  is attached to the PCB  303  via, for example, a lamination process. The PCB  303  is attached to the BGA/PGA adapter  304  using BGA solder balls  316  (only one ball  316  is shown).  
         [0019]    A conductor-plated via  315  is formed within the separation layer  302  and the PCB  303 . The conductor-plated via  315  may be formed by drilling a via into the separation layer  302  and the PCB  303 , plating the via with a conductor (e.g., copper), filling the plated via with an epoxy material, and then sealing the via at both ends with a conductor pad (e.g., comprising gold).  
         [0020]    A signal may travel between the processor  102  (FIG. 1) and the motherboard  103  (FIG. 1) by being conducted through the pin  305 , the BGA solder ball  316 , the conductor-plated via  315 , the BGA solder ball  313 , and the pin receptacle  314  (in either direction). Such a signal is probed by a conductive trace  308  that is coupled in series with a resistor R 2  and a compensation circuit  306 .  
         [0021]    The separation layer  302  enables a compensation circuit  306  to be located closer to a probing point  317  located on a signal path between the processor  102  and the motherboard  103 . Locating the compensation circuit  306  closer to the probing point  317  increases the operating bandwidth of the signal probing system  101  (i.e., enables the signal probing system  101  (FIG. 1) to accurately probe signals having higher frequencies). Furthermore, locating the compensation circuit  306  closer to the probing point  317  reduces circuit loading, which in turn reduces the attenuation of signals being probed by the signal probing system  101 .  
         [0022]    Certain motherboards may have one or more components that are in such close proximity to a processor that conventional processor-socket adapters may not be successfully coupled to the motherboards for the purpose of testing such processor.  
         [0023]    Locating compensation circuits  306  closer to respective probing points  317  allows the size of the PCB  303  to be reduced. This prevents the PCB  303  from colliding with components of a motherboard  103  that surround the designated location of a processor  102  as a user attempts to couple the PCB  303  to such designated location. As a result, the processor-socket adapter  201  may be used in conjunction with a wider variety of motherboards  103 .  
         [0024]    The compensation circuit  306  comprises a capacitor C 1  and a resistor R 1  coupled in parallel. The resistor R 2  may be coupled to the compensation circuit  306  circuit through a conductor-plated via  309  and a solder pad  310 - 1 . The compensation circuit  306  circuit may be coupled to the solder pad  307  through a solder pad  310 - 2 , conductor-plated vias  311 - 1  and  311 - 2 , and a conducting trace  312 .  
         [0025]    [0025]FIG. 5 is a flow chart depicting an embodiment of a method  500  for manufacturing a signal probing system  101 . The method  500  will be discussed with additional reference to components depicted in FIGS. 1-4. A PCB  303  (FIG. 3) is fabricated with buried resistors R 2  (FIG. 4), as indicated in block  501 . Alternatively, surface-mounted or etched resistors may be used instead of the buried resistors R 2 . The PCB  303  may also be fabricated to include conductor-plated vias  309 ,  311 - 1  and  311 - 2 , solder pads  307 ,  310 - 1 , and  310 - 2 , conductor-plated vias, conducting traces  312  (FIG. 4).  
         [0026]    A separation layer  302  (FIG. 3) is attached to the PCB  303 , as indicated in block  502 . The separation layer  302  may comprise, for example, fiber-glass (or some other dielectric), and may be attached to the PCB  303  using, for example, a lamination process. Conductor-plated vias  315  (FIG. 4) extending through the separation layer  302  and the PCB  303  are created, as indicated in block  503 . Each conductor-plated via  315  is coupled to a respective buried resistor R 2 .  
         [0027]    Resistors R 1  and capacitors C 1  (FIG. 4) are attached the PCB  303 , as indicated in block  504 . Each resistor R 1  is coupled in parallel to a respective capacitor C 1  and in series with a respective resistor R 2  and with a respective solder pad  307 .  
         [0028]    A processor socket  301  is attached to a separation layer  302 , and a BGA-PGA adapter  304  is attached to the PCB  303 , as indicated in blocks  505  and  506 , respectively. The steps depicted in blocks  505  and  506  may be performed using, for example, BGA solder balls. The processor socket  301  is configured to receive processor pins corresponding to a processor  102  (FIG. 1). The BGA-PGA adapter  304 , on the other hand, is configured to be plugged into a motherboard  103  (FIG. 1).  
         [0029]    One or more coaxial cable ribbons (FIG. 2) are attached to the PCB  303  through the solder pads  307 , as indicated in block  507 . The coaxial cable ribbon(s)  203  preferably comprise micro-coaxial cables that are much thinner than those used, for example, to provide input to a television set. One or more connector boards  202  (FIG. 2) is/are attached to respective coaxial cable ribbon(s), as indicated in block  508 . The connector board(s)  202  is/are configured to be coupled (directly or indirectly) to a testing instrument  104 .  
         [0030]    Note that some of the steps depicted in FIG. 5 may be performed in an order that is different than the illustrated order, including concurrently or in reverse order. For example, any of the steps depicted in blocks  505 ,  506 ,  507 , and/or  508  may be performed before or after any of the other steps depicted in such blocks.  
         [0031]    It should be emphasized that the above-described embodiments are merely possible examples, among others, of the implementations. Many variations and modifications may be made to the above-described embodiments. All such modifications and variations are intended to be included herein within the scope of the disclosure and protected by the following claims.