Abstract:
A data storage device (DSD) with improved manufacturing method. The DSD includes a main printed circuit board (PCB) that includes a first PCB connector and a second PCB connector. The DSD also includes a first flash card mounted over the main PCB and including a flash memory and a flash card connector configured to connect to the first PCB connector, and a second flash card mounted over the main PCB and including a flash memory and a flash card connector configured to connect to the second PCB connector. The first flash card and the second flash card are mounted over the main PCB in a plane substantially parallel with the main PCB. The main PCB can be mounted to a base before connecting the first and second flash cards, or the first and second flash cards can be mounted to the main PCB before mounting to the base.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application claims the benefit of U.S. Provisional Application No. 61/840,758, filed on Jun. 28, 2013, which is hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     A data storage device (DSD), such as a hard disk drive (HDD), a solid state drive (SSD), or solid state hybrid drive (SSHD), may include a System-on-a-Chip (SoC) and flash memory on a single, main printed circuit board (PCB). Additional flash memory may be mounted on a separate flash card, which is connected to the main PCB. The flash card may be placed above the main PCB, attached through a connector. 
     In some configurations, the flash card may be connected to the main PCB through two connectors. The connectors may be misaligned due to mechanical component tolerances stacking up, and manufacturing variances. The connector misalignment may cause stress in the flash card. 
    
    
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
       The features and advantages of the implementations of the present disclosure will become more apparent from the detailed description set forth below when taken in conjunction with the drawings. The drawings and the associated descriptions are provided to illustrate implementations of the disclosure and not to limit the scope of what is claimed. 
         FIG. 1A  is a view of part of a DSD according to an implementation of the present disclosure; 
         FIG. 1B  a side view of  FIG. 1A ; 
         FIG. 1C  is a conceptual diagram of connector placement on a main PCB of a DSD; 
         FIG. 2A  is an exploded view of a DSD according to an implementation of the present disclosure; 
         FIG. 2B  is an assembled view of a DSD according to another implementation of the present disclosure; 
         FIG. 3A  is an exploded view of a DSD according to an implementation of the present disclosure; 
         FIG. 3B  is a view of the base in  FIG. 3A ; 
         FIG. 3C  is a side view of the base in  FIG. 3A ; 
         FIG. 4A  is an exploded view of a DSD according to another implementation of the present disclosure; 
         FIG. 4B  is a view of a module from the DSD of  FIG. 4A ; 
         FIG. 4C  is a view of the base in  FIG. 4A ; 
         FIG. 4D  is a side view of the base in  FIG. 4A ; 
         FIG. 5A  is an exploded view of a DSD according to another implementation of the present disclosure; 
         FIG. 5B  is a view of the base in  FIG. 5A ; 
         FIG. 5C  is a side view of the base in  FIG. 5A ; 
         FIG. 6A  is an exploded view of a DSD according to an implementation of the present disclosure; 
         FIG. 6B  is a bottom view of a single twin daughter flash card in  FIG. 6A ; 
         FIG. 6C  is a view of the base in  FIG. 6A ; 
         FIG. 6D  is a view of the cover in  FIG. 6A ; 
         FIG. 7  is a flowchart of assembling a DSD according to an implementation of the present disclosure; and 
         FIG. 8  is a flowchart of assembling a DSD according to another implementation of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, numerous specific details are set forth to provide a full understanding of the present disclosure. It will be apparent, however, to one of ordinary skill in the art that the various implementations disclosed may be practiced without some of these specific details. In other instances, well-known structures and techniques have not been shown in detail to avoid unnecessarily obscuring the various implementations. 
     While the description herein refers generally to a solid state memory such as a NAND flash memory, it is understood that other implementations can include one or more of various types of solid state memory such as Chalcogenide RAM (C-RAM), Phase Change Memory (PC-RAM or PRAM), Programmable Metallization Cell RAM (PMC-RAM or PMCm), Ovonic Unified Memory (OUM), Resistance RAM (RRAM), NAND memory (e.g., single-level cell (SLC) memory, multi-level cell (MLC) memory, or any combination thereof), NOR memory, EEPROM, Ferroelectric Memory (FeRAM), Magnetoresistive RAM (MRAM), spin-transfer torque RAM (STT-RAM), other discrete non-volatile memory (NVM) chips, or any combination thereof. 
       FIG. 1A  presents a DSD  100  according to an implementation of the present disclosure.  FIG. 1B  presents a side view of the DSD  100 . The DSD  100  includes a base  110  and a main PCB  120 . The main PCB includes a plurality of components  123  and also includes a first PCB connector  122  along a first side  125 , and a second PCB connector  124  along a second side  126 . Due to space requirements, in particular in small form factor applications such as 2.5 in drives, additional components, such as flash memory, are mounted on a separate PCB, such as a flash card. Having the flash memory on a separate flash card allows for mounting components  123 , which may include an SoC, as well as traces for various connections (not shown). The flash card connects to the main PCB through the first PCB connector  122  and the second PCB connector  124 . 
     Due to manufacturing variances or tolerances, the flash card&#39;s connectors may not align perfectly with the first PCB connector  122  and the second PCB connector  124 .  FIG. 1C  shows an exaggerated view of possible misalignment. A flash card  150  is shown as an outline. The flash card  150  includes a first connector  151  and a second connector  152 , also shown in outline.  FIG. 1C  shows an extreme example of all four connectors being misaligned in different directions. In addition, a distance  136  between the first PCB connector  122  and the second PCB connector  124  may vary. 
     When the flash card  150  is installed onto the main PCB  120 , a large amount of force, for example 40+ lbs., may be required to overcome the misalignment of the connectors. This may cause unwanted flash card warping, unreliable connections, and other defects which may not be detected during factory testing but cause failures in the field when thermal expansion and/or shock events aggregate the misalignment issues. In addition, the connectors may not be pin-and-socket type connections and therefore more fragile. As the connector pitch (the width between pins) is reduced due to the increased number of pins needed, the stress from force fitting the flash card  150  is exacerbated. 
       FIG. 2A  shows a DSD  200  according to an implementation of the present disclosure. The DSD  200  includes a base  210 , and main PCB  220 , a first flash card  240 , and a second flash card  230 . The base  210  includes a standard standoff  211 , a component mount cavity  209 , which may be parts of a preconfigured base casting. The main PCB  220  includes a first PCB connector  222  and a second PCB connector  224 . The first flash card  240  includes a first edge  246 , a second edge  247  opposite the first edge  246 , and a third edge  248  connecting the first edge  246  and the second edge  247 , a plurality of flash memory  242 , a plurality of capacitors  244 , and a recess  249 . The second flash card  230  includes a first edge  236 , a second edge  237  opposite the first edge  236 , and a third edge  238  connecting the first edge  236  and the second edge  237 , a plurality of flash memory  232 , a plurality of capacitors  234 , a recess  239 , and a connector  235 . The connector  235  connects to the second PCB connector  224 . The first flash card  240  also has a connector (not shown) for connecting to the first PCB connector  222 . A pair of screw standoffs  214  receives a pair of screws  212  to mount the first flash card  240 , the second flash card  230 , and the main PCB  220  to the base  210 . Rather than a single flash card, such as the flash card  150 , the flash memory is mounted on two separate flash cards, which may be symmetrical. In other words, the two flash cards may have the same design or layout, and one being rotated to fit on the other side. 
       FIG. 2B  presents a partially assembled view of a DSD, the cover not shown to showcase the first flash card  240  and the second flash card  230 . As seen in  FIG. 2B , the main PCB  220 , the first flash card  240  and the second flash card  230  generally reside in an interior cavity defined by at least the base  210 , and a cover (not shown). A first clip  225  occupies the recess  249  and the recess  239  to connect the first flash card  240  and the second flash card  230  near the first edge  246  and the first edge  236 . A second clip  226  similarly connects the first flash card  240  and the second flash card  230  near the second edge  247  and the second edge  237 . The first clip  225  and the second clip  226  provide support and stability to the first flash card  240  and the second flash card  230 , such that the first flash card  240  and the second flash card  230  are substantially parallel to the main PCB  220 . 
     By separating a conventional flash card into two or more flash cards, the misalignment stress is reduced. Although the present disclosure describes a dual flash card configuration, more flash cards may be used as needed. The dual flash card approach de-couples the connectors, which reduces stress on the cards as well as the pins. Because misalignment is reduced, the amount of force required to mate each flash card to the main PCB is reduced. In addition, having more than one flash card may simplify designs and fabrication as the lengths of traces may be reduced. 
     The two flash cards may be twin flash cards in certain implementations, allowing for interchangeable flash cards, which alleviates manufacturing and inventory issues. The implementations below describe various example arrangements for mounting and connecting the flash cards. 
       FIG. 3A  presents one implementation of a flash card in a DSD  300 , utilizing two standoffs and two hard stops. The DSD  300  includes a base  310 , a main PCB  320 , a first flash card  330 , a second flash card  340 , a cover  350 , and a label  355 . 
     The base  310  has a feature  311  and a cavity  309 , which may provide space for additional components such as a capacitor bank. The main PCB  320  includes a first PCB connector  324  and a second PCB connector  322 . The first flash card  330  includes a plurality of flash memory  332  as well as a plurality of capacitors  334 . A connector  335  connects the flash card  330  to the main PCB  320 . The flash card  330  also includes recesses  339 . The second flash card  340  includes a plurality of flash memory  342  as well as a plurality of capacitors  344 , and recesses  349 . Although not visible in  FIG. 3A , the flash card  340  also includes a connector to mate with the PCB connector  322 . The cover  350  includes hard stops  356 . A series of screws  352  attach the cover  350  to the base  310 , as shown in  FIG. 3A . 
     The main PCB  320  is secured to the base  310  by two standoffs  314  as well as two screws  352 . The first flash card  330  is secured to the base  310  via a screw  312  mating with a standoff  314 . Using only one screw per flash card allows for more space on the main PCB  320 , rather than using space for more screws/standoffs. However, in this design, a portion of the flash card  330  opposite from the standoff  314  is not secured or is otherwise free-floating. This may allow that portion of the flash card  330  to vibrate, hitting other components or loosening connections. To secure this end of the flash card  330 , the cover  350  has a hard stop  356  which braces the flash card  330 , preventing excessive vibration or movement. Similarly, the second flash card  340  is secured by a standoff  314  and a hard stop  356 . As further seen in  FIG. 3A , the corners of the flash card  330  and the flash card  340  have cutouts to better fit with the main PCB  320  and the base  310 . In addition, although the DSD  300  generally uses two standoffs  314  and two hard stops  356 , in other implementations more or less standoffs  314  and/or hard stops  356  may be used, located as needed on the base  310  and/or the cover  350 . For example, more hard stops  356  may be desirable to better brace the flash card  330  and the flash card  340 . However, depending on space requirements, there may not be room for additional hard stops  356 . 
       FIGS. 3B and 3C  show the base  310 . The base  310  may be a base casting interchangeably used for various other DSDs. As such, the base  310  has features  311 , which may provide a mounting connection for components, or as seen in  FIG. 3A , remain unused. The base  310  may further have one or more hard stops  313 , which can provide support for the main PCB  320  or other components. As seen in  FIG. 3C , the base  310  does not have any protrusions extending beyond the height of the sidewall. This may be suitable for various device profiles, such as 7 mm. 
       FIGS. 4A and 4B  present another flash card design in a DSD  400 , using four standoffs, according to an implementation of the present disclosure. The DSD  400  includes a base  410 , a main PCB  420 , a first flash card  430 , a second flash card  440 , and a cover  450 . The main PCB  420  includes a PCB connector  424  for mating with a connector  435  of the flash card  430 . The main PCB  420  includes another PCB connector (not shown) for mating with the flash card  440 . The cover  450  includes a label  455 , and is attached to the base  410  by screws  452 . 
     The flash card  430  includes a plurality of flash memory  432  and a plurality of capacitors  434 . The flash card  430  includes a first edge  436  and a second edge  437 , and a pair of recesses  439  near the first edge  436  and the second edge  437 . Similarly, the flash card  440  includes a plurality of flash memory  442  and a plurality of capacitors  444 . The flash card  440  includes a pair of recesses  449  near a first edge  446  and a second edge  447 . 
     A pair of standoffs  414  and screws  412  connects the flash card  430  to the main PCB  420 . Likewise, a pair of standoffs  414  and screws  412  connects the flash card  440  to the main PCB  420 . The standoffs  414  may be screwed into the main PCB  420  or may be otherwise mounted or integrated onto the main PCB  420 . The two standoffs  414  for each flash card, which are located on both sides of the PCB connector  424 , occupy more space on the main PCB  420 , due to the extra mount. However, this configuration provides a more robust assembly, durable against shocks and vibrations. 
     Unlike the DSD  300 , which uses hard stops  356 , the DSD  400  does not utilize hard stops to secure the flash card  430  and the flash card  440 . Due to manufacturing variances or tolerances, a hard stop may not perfectly align with the final mounted position of a flash card. With vibration, the hard stop may even damage or otherwise loosen the flash card. The DSD  400  uses screws  412  and standoffs  414 , but in implementations where the design does not allow for standoffs, hard stops may be used instead. 
     A first clip  425  attaches to the recess  439  near the first edge  436  of the flash card  430  and the recess  449  near the first edge  446  of the flash card  440  to connect the flash card  430  and the flash card  440 . A second clip  426  similarly connects the flash card  430  and the flash card  440  near the second edge  437  of the flash card  430  and the second edge  447  of the flash card  440 . The clip  425  and the clip  426  provide stability to the flash card  430  and the flash card  440 , similar to a single flash card, without adding undue stress. The main PCB  420  attaches to the base through screws  452  and  416 , as seen in  FIG. 4A . A pair of hard stops  413  (only one visible in  FIG. 4A ) provides additional support to the main PCB  420 , which may help reduce bending due to the added pressure of the flash card  430  and the flash card  440 . 
     This configuration allows the flash card  430  and the flash card  440  to be mounted to the main PCB  420 , forming a module  401  as seen in  FIG. 4B . Assembling the module  401  reduces the risk of board deflection during the assembly of the DSD  400 . The module  401  may be tested before mounting to the base  410 , allowing for easier testing and reducing the likelihood of a teardown for replacement of components before completing the assembly. For example, if there are issues with initializing the flash memory  432  and the flash memory  442 , rather than tearing down the DSD by removing the base, the faulty flash memory can be replaced by removing the corresponding flash card. Since the flash card  430  and the flash card  440  are attached by two screws  412  each to the main PCB  420 , removal requires removing two screws  412  and the clip  425  and the clip  426 . The clip  425  and the clip  426  may optionally be left unconnected until testing is complete. Alternatively, the main PCB  420  may be mounted to the base  410  first, followed by the flash card  430  and the flash card  440 . 
       FIGS. 4C and 4D  show the base  410 . The base  410  may be a base casting interchangeably used for various other DSDs. For example, the base  410  may be the same as the base  310 . The base  410  has features  411 , which may provide a mounting connection for components, or as seen in  FIG. 4A , remain unused. The base  410  has one or more hard stops  413 , which can provide support for the main PCB  420  or other components. As seen in  FIG. 4D , the base  410  does not have any protrusions extending beyond the height of the sidewall. This may be suitable for various device profiles, such as a 7 mm device profile. 
       FIGS. 5A-5C  depict another implementation of a DSD  500 . As seen in  FIG. 5A , the DSD  500  includes a base  510 , a main PCB  520 , a first flash card  530 , a second flash card  540 , and a cover  550 . The cover  550  attaches to the base  510  through screws  552 . The main PCB  520  includes a PCB connector  524  for mating with a connector  535  of the flash card  530 . The main PCB  520  includes another PCB connector (not shown) for mating with the flash card  540 . 
     The flash card  530  includes a plurality of flash memory  532  and a plurality of capacitors  534 . The flash card  530  includes a first edge  536  and a second edge  537 , and a pair of recesses  539  near the first edge  536  and the second edge  537 . Similarly, the flash card  540  includes a plurality of flash memory  542  and a plurality of capacitors  544 . The flash card  540  includes a pair of recesses  549  near a first edge  546  and a second edge  547 . 
     A first clip  525  attaches to the recess  539  near the first edge  536  of the flash card  530  and the recess  549  near the first edge  546  of the flash card  540  to connect the flash card  530  and the flash card  540 . A second clip  526  similarly connects the flash card  530  and the flash card  540  near the second edge  537  of the flash card  530  and the second edge  547  of the flash card  540 . A screw  512  connects with a standoff  514  over the main PCB  520  to mount the flash card  530  to the base  510 . Another screw  512  connects with an integrated standoff  511  of the base  510  to mount the flash card  530  to the base  510 . The flash card  540  is similarly mounted. 
     Using screws  512  to secure the corners of the flash card  530  and the flash card  540  generally provides a robust assembly, protecting against shocks and vibrations. In addition, less space is used on the main PCB, particularly space that may be used for traces, such as near the PCB connector  524 . 
       FIGS. 5B and 5C  show views of the base  510 . The base  510  includes a pair of protrusions or integrated standoffs  511 , which extend above a height of the base  510 , as seen in  FIG. 5C . In some implementations, the integrated standoffs  511  may be grinded down to not extend beyond the height of the base  510 . For example, in a 7 mm profile, the integrated standoffs  511  may be shaved off, whereas in a 15 mm profile, the integrated standoffs  511  may not be shaved off. A pair of hard stops  513  may provide further support to the main PCB  520 . 
       FIGS. 6A-6D  depict another implementation of a DSD  600 . As seen in  FIG. 6A , the DSD  600  includes a base  610 , a main PCB  620 , a first flash card  630 , a second flash card  640 , and a cover  650 . The cover  650  attaches to the base  610  through screws  652 . The main PCB  620  includes a PCB connector  624  for mating with a connector  635  of the flash card  630 . The main PCB  620  includes another PCB connector (not shown) for mating with the flash card  640 . 
     The flash card  630  includes a plurality of flash memory  632  and a plurality of capacitors  634 . The flash card  630  includes a first edge  636  and a second edge  637 , and a pair of recesses  639  near the first edge  636  and the second edge  637 . Similarly, the flash card  640  includes a plurality of flash memory  642  and a plurality of capacitors  644 . The flash card  640  includes a pair of recesses  649  near a first edge  646  and a second edge  647 .  FIG. 6B  illustrates an underside view of the flash card  630 . As seen in  FIG. 6B , the flash memory  632  and the capacitors  634  may be mounted on a bottom or underside  631  of the flash card  630 , near where the connector  635  is disposed. A third edge  638 , opposite the connector  635 , connects the first edge  636  and the second edge  637 . 
     A first clip  625  attaches to the recess  639  near the first edge  636  of the flash card  630  and the recess  649  near the first edge  646  of the flash card  640  to connect the flash card  630  and the flash card  640 . A second clip  626  similarly connects the flash card  630  and the flash card  640  near the second edge  637  of the flash card  630  and the second edge  647  of the flash card  640 . A pair of screws  612  connects with a pair of integrated standoffs  611  of the base  610  to mount the flash card  630  to the base  610 . The flash card  640  is similarly mounted. 
     Using screws  612  to secure the corners of the flash card  630  and the flash card  640  provides a robust assembly, protecting against shocks and vibrations. In addition, less space is used on the main PCB, particularly space that may be used for traces, such as near the PCB connector  624 . In addition, the use of integrated standoffs  611  rather than standoffs on the main PCB reduces assembly time, as the standoffs do not need to be mounted. 
       FIG. 6C  shows the base  610 . The base  610  includes two pairs of protrusions or integrated standoffs  611 , which extend above a height of the base  610 . In some implementations, the integrated standoffs  611  may be grinded down to not extend beyond the height of the base  610 . As seen in  FIG. 6C , the integrated standoffs  611  may have a flat portion, which may help in aligning the cover  650  and/or other components during assembly. A pair of hard stops  613  may provide further support to the main PCB  620 . 
       FIG. 6D  shows the cover  650 . The cover  650  includes two pairs of alignment guides  655 . The alignment guides  655  assist in aligning the four corners of the cover  650  to the four corners of the base  610 . The alignment guides  655  may further assist in preventing the integrated standoffs  611  from being misaligned. 
       FIG. 7  presents a flowchart  700  of a fabrication method according to an implementation of the present disclosure. The flowchart  700  may correspond to a fabrication process for the DSDs  300 ,  500 , and  600 . 
     At  710 , a main PCB, such as the main PCBs  320 ,  520 , or  620 , is secured to a base, such as the bases  310 ,  510 , or  610 , respectively. As described above, a combination of screws, standoffs, adhesives and/or other mounting mechanisms may be used to mount the main PCB to the base. At  720 , a first flash card, such as the flash cards  330 ,  530 , or  630 , is secured to the base. The first flash card may be secured by screws, standoffs, adhesives and/or other mounting mechanisms. At  730 , a second flash card, such as the flash cards  340 ,  540 , or  640 , is secured to the base. The second flash card may be secured by screws, standoffs, adhesives and/or other mounting mechanisms. 
     At  740 , a first clip, such as the clips  325 ,  525 , or  625 , is attached to a first edge of the first flash card, such as the edges  336 ,  536 , or  636 , respectively, as well as a first edge of the second flash card, such as the edges  346 ,  546 , or  646 , respectively. At  750 , a second clip, such as the clips  326 ,  526 , or  626 , is attached to a second edge of the first flash card, such as the edges  337 ,  537 , or  637 , respectively, as well as a second edge of the second flash card, such as the edges  347 ,  547 , or  647 , respectively. 
     At  760 , a cover, such as the covers  350 ,  550 , or  650 , is secured to the base. As described above, the cover may be secured to the base by screws, standoffs, adhesives and/or other mounting mechanisms. 
       FIG. 8  presents a flowchart  800  of a fabrication method according to an implementation of the present disclosure. The flowchart  800  may correspond to a fabrication process for the DSD  400 . 
     At  810 , a main PCB, such as the main PCB  420 , is provided. The main PCB has a first and second PCB connector, such as the PCB connector  424 . At  820 , a first flash card, such as the flash card  430 , is secured to the base. The first flash card may be secured by screws, standoffs, adhesives and/or other mounting mechanisms. At  830 , a second flash card, such as the flash card  440 , is secured to the base. The second flash card may be secured by screws, standoffs, adhesives and/or other mounting mechanisms. 
     At  840 , a first clip, such as the clip  425 , is attached to a first edge of the first flash card, such as the edge  436 , as well as a first edge of the second flash card, such as the edge  446 . At  850 , a second clip, such as the clip  426 , is attached to a second edge of the first flash card, such as the edge  437 , as well as a second edge of the second flash card, such as the edge  447 . 
     After  850 , a module, such as the module  401 , is formed. The module may be tested, such as testing connections or integrity of components. Because the module is not otherwise mounted to a base, testing may be simplified as ports and connections are more accessible, and components may be more easily replaced. 
     At  860 , a main PCB, such as the main PCB  420 , is secured to a base, such as the base  410 , respectively. As described above, a combination of screws, standoffs, adhesives and/or other mounting mechanisms may be used to mount the main PCB to the base. 
     At  870 , a cover, such as the cover  450 , is secured to the base. As described above, the cover may be secured to the base by screws, standoffs, adhesives and/or other mounting mechanisms. 
     The foregoing description of the disclosed example implementations is provided to enable any person of ordinary skill in the art to make or use the implementations in the present disclosure. Various modifications to these examples will be readily apparent to those of ordinary skill in the art, and the principles disclosed herein may be applied to other examples without departing from the spirit or scope of the present disclosure. The described implementations are to be considered in all respects only as illustrative and not restrictive and the scope of the disclosure is, therefore, indicated by the following claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.