Patent Publication Number: US-6663437-B2

Title: Stacked modular jack assembly having built-in circuit boards

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application is a continuation-in-part of U.S. patent application Ser. No. 10/037,061, filed on Nov. 8, 2001; now U.S. Pat. No. 6,506,080 and is related to U.S. Patent Applications respectively entitled “HIGH FREQUENCY MODULAR JACK CONNECTOR” invented by the same inventors as this patent application, entitled “STACKED MODULAR JACK ASSEMBLY HAVING HIGHLY MODULARIZED ELECTRONIC COMPONENTS” invented by the same inventors as this patent application, entitled “MODULAR JACK ASSEMBLY HAVING IMPROVED POSITIONING MEANS” invented by the same inventors as this patent application, and entitled “STACKED MODULAR JACK ASSEMBLY HAVING IMPROVED ELECTRIC CAPABILITY” invented by the same inventors as this patent application, and all assigned to the same assignee with this application. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a stacked modular jack assembly, and particularly to a stacked LAN (Local Area Network) jack assembly having built-in circuit boards each having signal conditioning components thereon for ensuring high signal transmission performance of the jack assembly. 
     2. Description of Related Art 
     It is quite common to use modular jacks for the data transmission in high speed applications such as IEEE 802.3 10Base-T or 100Base-T local area networks. A common problem to these high speed modular jacks is their tendency to emit high frequency radiation. There is also a need to provide means for suppressing undesirable noise. 
     Noise suppressors or signal conditioning components, such as common mode choke coils, are known in the art. The noise suppressors are mounted on a mother board on which the modular jack is seated. The noise suppressors are electrically connected with the modular jack by traces on the mother board. However, such signal conditioning components consume board real estate, which could otherwise be used for other circuitry. Furthermore, since the signal conditioning components are distant from the modular jack, the signal traces required to route the signals from the modular jack to the signal conditioning components degrade the signal integrity somewhat, thereby lowering the signal-to-noise ratio. 
     Stewart, headquartered in Glen Rock, Pa., posted an article, entitled “MagJack Family of Modular Jacks with Integrated Magnetics” on the Internet website address, http://www.stewartconnector.com/pdfs/magjkfypdf. This article introduces a series of magjack modular connectors each having integrated magnetic components housed within a jack body for protecting signals from internally and externally generated noise. Because the magnetic components are integrated into the jack itself, valuable board real estate is obviously saved. 
     U.S. Pat. No. 5,069,641, assigned to Murata Manufacturing Co., Ltd., discloses a modular jack assembly comprising a dielectric housing and a printed circuit board disposed within the housing. The printed circuit board contains noise suppressors. A common mode choke coil and a three-terminal capacitor arrangement is used as a typical of the noise suppressor. The printed circuit board is fitted with contactors and terminals respectively for contacting with a modular plug and for mounting the modular jack assembly on a mother board. The contactors and the terminals are electrically connected with the noise suppressors by traces on the printed circuit board. 
     U.S. Pat. Nos. 5,587,884 and 5,647,767, both assigned to The Whitaker Corporation, each disclose a modular jack assembly comprising an insulating housing and an insert subassembly received in the housing. The insert subassembly includes front and rear insert members. The front insert member has contact terminals encapsulated therein for mating with a modular plug. The rear insert member has a printed circuit board and leads encapsulated therein. The printed circuit board contains signal conditioning components such as common mode choke coils. The leads extend downwardly for electrically connecting to external circuits, such as a mother board. The terminals and the leads are soldered to the printed circuit board and electrically connected with the signal conditioning components by traces on the printed circuit board. 
     U.S. Pat. No. 5,687,233, assigned to Maxconn Incorporated, discloses a modular jack assembly addressing the problem encountered in the &#39;884 and &#39;767 patents. The modular jack assembly employs a various of signal conditioning components such as capacitors and magnetic coils to provide sufficient conditioning of data transmission. Signal pins are divided into a contact pin array and a mounting pin array. The two pin arrays are electrically coupled through an internal printed circuit board (PCB) which carries the capacitors and magnetic coils. However, because the capacitors and magnetic coils are all mounted on the same printed circuit board, mutual interference between the signal conditioning components may also be a problem. 
     Recently, in order to save valuable real estate of mother boards in electronic devices, modular jacks are developed to be arranged in a stacked manner. When the stacked jack is used in high speed applications and required to have better signal transmission performance, a number of signal conditioning components will be mounted onto a PCB which is received in the stacked jack. The PCB is an expensive multi-layer printed circuit board so that it can have sufficient conductive lines to interconnect the signal conditioning components in a predetermined pattern. In addition, there is no available space on the PCB for more electrical components needed for suppressing crosstalk between adjacent contacts. 
     Hence, the present invention aims to provide a stacked jack assembly having an additional built-in PCB on which some signal conditioning components are mounted to thereby overcome the disadvantages of the prior art. 
     SUMMARY OF THE INVENTION 
     Accordingly, a first object of the present invention is to provide a stacked modular jack assembly having built-in circuit boards each with signal conditioning components attached thereon for achieving better signal transmission performance therethrough. 
     A second object of the present invention is to provide a modular jack assembly having built-in circuit boards each with signal conditioning components attached thereon for conditioning signals, and each circuit board having a simplified circuit design. 
     In order to achieve the objects set forth, an electrical connector assembly in accordance with the present invention comprises an insulating housing and an electrical subassembly disposed within the housing. The electrical subassembly includes first and second contact array assemblies each having a PCB and a plurality of contacts soldered on the PCB, a pair of magnetic modules respectively connected with the first and second PCBs, and a third PCB containing signal conditioning components. Each magnetic module has upper pins, lower pins for soldering to a mother board and magnetic coils connecting between the upper and lower pins via some of the upper pins thereof. The others of the upper pins of the magnetic modules are electrically connected to the signal conditioning components on the third PCB. 
     Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of an electrical connector assembly in accordance with the present invention; 
     FIG. 2 is a front exploded perspective view of the connector assembly of FIG. 1; 
     FIG. 3 is a rear perspective view of an insulating housing of the connector assembly; 
     FIG. 4 is a partially assembled view of the connector assembly showing an electrical subassembly of the present invention disposed within the insulating housing and an LED module to be assembled within the insulating housing; 
     FIGS. 5 a  and  5   b  are exploded perspective views of the electrical subassembly of FIG. 4 taken from different perspectives; 
     FIG. 6 is an exploded perspective view of a magnetic module assembly of the present invention; 
     FIGS. 7 a  and  7   b  are perspective views of upper and lower contact array assemblies of the present invention with carriers not severed therefrom; and 
     FIG. 8 is a cross-sectional view of the connector assembly taken along section line  8 — 8  of FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made in detail to the preferred embodiment of the present invention. 
     Referring to FIGS. 1 and 2, an electrical connector assembly  1  in accordance with the present invention comprises an insulating housing  2 , an electrical subassembly  3  disposed within the insulating housing  2 , an LED (Light-Emitting Diode) module  6  secured to the housing  2  for functioning as a visual indicator and a shell  8  optionally enclosing the housing  2  for EMI (Electromagnetic Interference) protection. In the preferred embodiment of the present invention, the electrical connector assembly  1  is a stacked LAN (Local Area Network) jack assembly for high speed signal transmission. 
     Referring to FIG. 3 in conjunction with FIGS. 1 and 2, the insulating housing  2  defines upper and lower receiving cavities  21 ,  22  in a front mating face  200  for receiving modular plugs (not shown), and a receiving space  23  in a rear face  202  communicating with the upper and lower receiving cavities  21 ,  22  through upper and lower channels  24 ,  25 . The upper and lower receiving cavities  21 ,  22  share a partition wall  20  therebetween. 
     The housing  2  defines a pair of upper and lower holes  210 ,  220  located at four corners of the front mating face  200 . Each lower hole  220 , near a bottom mounting face  204 , extends into the housing  2  for a predetermined length for receiving therein a standard LED  5 . The LED  5  is inserted into the corresponding lower hole  220  with its right-angled legs fitted in slits  221  formed in the bottom mounting face  204 . Each upper hole  210 , near a top face  206 , extends in the housing  2  from the front mating face  200  to the receiving space  23 . The housing  2  defines a plurality of upper and lower slits  214 ,  224  extending through an intermediate wall  208  between the receiving cavities  21 ,  22  and the receiving space  23 . 
     The housing  2  defines two pairs of grooves  26  extending in a back-to-front direction of the housing  2  beside the receiving space  23 . The grooves  26  extend into the upper and lower receiving cavities  21 ,  22  through the upper and lower channels  24 ,  25 . The housing  2  further defines a pair of recesses  28  beside the receiving space  23  and offsetting from each other in a vertical direction. In addition, the housing  2  has a pair of positioning posts  29  downwardly extending from the bottom mounting face  204  for being received in corresponding holes of a mother board (not shown) on which the electrical connector assembly  1  is to be mounted. 
     Referring to FIGS. 5 a  and  5   b  in conjunction with FIG. 2, the electrical subassembly  3  comprises a magnetic module assembly  30 , upper and lower contact array assemblies  32 ,  34  positioned above the magnetic module assembly  30 , and a third printed circuit board (PCB)  36  disposed above the upper contact array assembly  32 . 
     Referring to FIG. 6, the magnetic module assembly  30  includes front and rear magnetic modules  300 ,  300 ′ located back to back and a metal plate  4  disposed between the front and rear magnetic modules  300 ,  300 ′. The front and rear magnetic modules  300 ,  300 ′ are near identical in structure. The front and rear magnetic modules  300 ,  300 ′ each include a container  302  ( 302 ′), upper and lower pins  304 ,  306  ( 304 ′,  306 ′) respectively disposed on upper and lower portions of the container  302  ( 302 ′), and a plurality of magnetic coils  31  ( 31  ′) housed within the container  302  ( 302 ′) and connecting with the upper and lower pins  304 ,  306  ( 304 ′,  306 ′), which is schematically shown in FIG.  8 . The upper pins  304  ( 304 ′) are divided into first and second pin arrays  304   a ,  304   b  ( 304   a ′,  304   b ′). The metal plate  4  has a plane body  40  sandwiched between the front and rear magnetic modules  300 ,  300 ′, and a plurality of tabs  42  extending forwardly and rearwardly from top and bottom edges of the plane body  40  and received in slots of the containers  302 ,  302 ′ for joining the front and rear magnetic modules  300 ,  300 ′ together. Upper and lower legs  44 ,  46  respectively extend upwardly and downwardly from top and bottom edges of the plane body  40 . The lower leg  46  is bent to form a right-angled tail aligned with the corresponding lower pins  306 ′ of the rear magnetic module  300 ′. The metal plate  4  further forms a pair of offsetting projections  48  respectively on side edges thereof. The metal plate  4  electrically shield and isolate the front and rear magnetic modules  300 ,  300 ′. 
     Referring to FIGS. 7 a  and  7   b  in conjunction with FIGS. 5 a  and  5   b , the upper and lower contact array assemblies  32 ,  34  are similar in structure. The upper and lower contact array assemblies  32 ,  34  have respective first and second printed circuit boards (PCBs)  320 ,  340  and respective first and second contact strips  321 ,  341  soldered on the first and second PCBs  320 ,  340 . The first and second contact strips  321 ,  341  include respective first and second signal contacts  322 ,  342 , respective first and second side conductors  325 ,  345  each with serrations formed thereon and respective first and second carriers  323 ,  343 . The first and second side conductors  325 ,  345  are respectively soldered on opposite side edges of the first and second PCBs  320 ,  340 . The first and second signal contacts  322 ,  342  have respective first and second tail portions  3220 ,  3420  respectively soldered on solder pads of the first and second PCBs  320 ,  340 , and first and second mating portions  3222 ,  3422  extending from the respective first and second tail portions  3220 ,  3420  and being angled rearwardly from respective first and second front edges  3200 ,  3400  of the first and second PCBs  320 ,  340  to be located above and below respective upper and lower faces of the PCBs  320 ,  340  on which conductive traces  326 ,  346  (FIGS. 5 a  and  5   b ) are formed. The solder pads to which the first and second contacts  322 ,  342  are soldered, and the conductive traces  326 ,  346  are so designed and arranged that they can affect cross-talk between the first contacts  322  and the second contacts  342 , respectively. The related description of the solder pads and the conductive traces on the first and second PCBs  320 ,  340  are disclosed in patent application Ser. No. 10/037,061 filed on Nov. 8, 2001 and entitled “RJ MODULAR CONNECTOR HAVING SUBSTRATE HAVING CONDUCTIVE TRACE TO BALANCE ELECTRICAL COUPLINGS BETWEEN TERMINALS”. The disclosures of the &#39;061 application are wholly incorporated herein by reference. 
     The first and second PCBs  320 ,  340  define first and second plated through holes  3204   a ,  3404   a  and first and second clear through holes  3204   b ,  3404   b  at respective first and second rear portions  3202 ,  3402 , and respective first and second clear apertures  3206 ,  3406  therein. The term “plated” before through holes or through apertures means that there is conductive material plated on walls defining the through holes or through apertures, while the term “clear” means that there is no conductive material on walls defining the through holes or through apertures. 
     The third PCB  36  contains a plurality of signal conditioning components such as capacitors  360  and resistors  362  used for signal conditioning and termination. The third PCB  36  defines a plurality of third plated through holes  364  and a third plated aperture  366  therein. 
     The first upper pin array  304   a ′ of the rear magnetic module  300 ′ is soldered to the second plated through holes  3404   a  of the second PCB  340  and electrically connected with the second contacts  342  by wires (not labeled) on the second PCB  340 . The first upper pin array  304   a  of the front magnetic module  300  first penetrates through the second clear through holes  3404   b  and then are soldered to the first plated through holes  3204   a  of the first PCB  320  and electrically connected with the first contacts  322  by wires (not labeled) on the first PCB  320 . The second upper pin arrays  304   b ,  304   b ′ of the front and rear magnetic modules  300 ,  300 ′ penetrate through the second and first clear through holes  3404   b ,  3204   b  to be soldered to the third plated through holes  364  of the third PCB  36 . At the same time, the upper leg  44  of the metal plate  4  penetrates through the second and first clear apertures  3406 ,  3206  of the second and first PCBs  340 ,  320  to be soldered to the third plated aperture  366  of the third PCB  36 . 
     It can be seen that when the modular jack assembly  1  engages with the modular plugs, noise received through the first and second contacts  322 ,  342  is respectively reduced by the magnetic coils  31 ,  31 ′ of the front and rear magnetic modules  300 ,  300 ′. 
     It is noted that the second upper pin arrays  304   b ,  304   b ′ of the front and rear magnetic modules  300 ,  300 ′ are connected to the capacitors  360  and the resistors  362  via circuit traces (not labeled) on the third PCB  36 . The third plated through hole  366  is defined in the circuit trace of the third PCB  36 , and the upper and lower legs  44 ,  46  of the metal plate  4  function as grounding terminals for respectively soldering with the third PCB  36  and the mother board. A majority of the upper and lower pins  304 ,  306  ( 304 ′,  306 ′) are connected with each other through the magnetic coils  31  ( 31 ′). 
     Referring to FIGS. 2 and 4, the LED module  6  includes an insulating carrier  60  with leads  68  overmolded therein and a pair of standard LEDs  66  electrically connecting with the leads  68 . The carrier  60  has a base portion  62  and a pair of limbs  64  forwardly perpendicularly extending from a top edge of the base portion  60 . The leads  68  have legs  680  downwardly extending beneath a bottom edge of the base portion  62  for soldering to the mother board. 
     In assembly, the electrical subassembly  3  is inserted into the housing  2  through the receiving space  23  in the rear face  202 . The first and second PCBs  320 ,  340  of the upper and lower contact array assemblies  32 ,  34  move forwardly respectively through the upper and lower channels  24 ,  25  of the housing  2  until the first and second mating portions  3222 ,  3422  of the first and second contacts  322 ,  342  respectively extend into the upper and lower receiving cavities  21 ,  22  through the upper and lower slits  214 ,  224 . The first and second rear portions  3202 ,  3402  of the first and second PCBs  320 ,  340 , the magnetic module assembly  30  and the third PCB  36  are disposed in the receiving space  23 . During this procedure, the first and second side conductors  325 ,  345  on the first and second PCBs  320 ,  340  are received in the corresponding grooves  26  for positioning and guiding the upper and lower contact array assemblies  32 ,  34 . The pair of offsetting projections  48  of the metal plate  4  is received in the offsetting recesses  28  of the housing  2  for positioning the electrical subassembly  3 . Therefore, the electrical subassembly  3  is ensured to be accurately inserted into the housing  2 . Finally, the serrations on the first and second side conductors  325 ,  345  of the first and second PCBs  320 ,  340  have an interferential engagement with the housing  2  in the grooves  26 . 
     It is noted that the first and second carriers  323 ,  324  of the first and second contact strips  321 ,  341  are removed therefrom before the electrical subassembly  3  is assembled to the housing  2 . 
     The shell  8  then encloses the housing  2  for EMI protection. The LED module  6  is finally secured to the housing  2  in a back-to-front direction. The LEDs  66  are inserted into the upper holes  210  of the housing  2  and can be visible from the front mating face  200 . The limbs  64  are received in slots  212  (FIG. 3) defined below the upper holes  210  of the housing  2 . The base portion  62  abuts against a rear wall  80  (FIG. 8) of the shell  8  with protrusions  620  (FIG. 2) keying into the housing  2 . 
     Although the preferred embodiment of the present invention only discloses an electrical subassembly used in a dual-port modular jack, it can be understood that a single-port modular jack can be constructed by modifying the electrical subassembly of the dual-port modular jack by removing one contact array assembly and one magnetic module therefrom. 
     In the present invention, since the signal conditioning components, i.e., the capacitors  360  and the resistors  362  are located at an additional PCB, i.e., the third PCB  36 , the first and second PCBs  320 ,  340  no longer need to be the expensive multi-layer printed circuit boards, but only much cheaper single-layer printed circuit boards. The third PCB  36  is also a single-layer printed circuit board. 
     It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.