KingMAX TinyBGA PC133 SDRAM DIMM - HotHardware

KingMAX TinyBGA PC133 SDRAM DIMM

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The Kingmax TinyBGA PC133 SDRAM DIMM
A New Form Factor In PC Memory Technology

June 14, 2000 By Dave "Davo" Altavilla

 

We've said this before and the same rings true time and time again, the PC Hardware Industry always has a place for something new and innovative.  Too often products are brought to market with a "me too" approach and there is little to differentiate them from the rest of crowd.  We are always looking for the products that stand out, here at HotHardware and the Kingmax "TinyBGA" SDRAM DIMM Module is one of those products. 

So, what makes this memory module so different from all the other hundreds of modules offered in the memory market?  In a word, "packaging".  Most consumers will purchase a product in a "slicker" more interesting package even if its performance or features are comparable to its plain vanilla counterpart.  The Kingmax "TinyBGA" SDRAM Module not only has a different package ( and we are not talking the box it ships in ) but there are specific technical merits to its different and innovative design.

 
The TinyBGA DIMM Specifications / Features
Itsy Bitsy....

Click all images for full view


  • 3.3V Unbuffered 168 Pin DIMM

  • 4K Self Refresh

  • 2K E2 PROM for SPD (Serial Presence Detect)

  • 128MB DIMM Consisting of 16 8MX8 Synch SDRAM chips rated at 7.5 ns

  • 1" High PCB - Double Sided Component Mounting

  • CAS3 Latency - Rated at 133MHz.

 

Those SDRAM chips look small don't they?  Look again...

Just how small are they compared to a standard SDRAM chip?  TINY....

Alright then, let's have a keen look at the obvious here.  This thing is small.  The PCB itself measures only 1" high versus most standard modules which stack up to about an 1" and 1/4 to an 1" and 3/8ths.  The reason for this small footprint of the TinyBGA DIMM, is the fact that it utilizes BGA packaging for its SDRAM chips.  BGA, an acronym representing the words "Ball Grid Array", is a type of semiconductor packaging that utilizes tiny solder balls on the bottom of the device versus wire leads protruding out of the sides.  This allows for a much smaller overall chip size due to the fact that a smaller PCB and "chip and wire" interconnect internally to the device, can be used.  Standard TSOP (Thin Small Outline Package) SDRAM chips utilize bulkier wire "Lead Frames" internally and also have to incorporate leads from the sides of the package, to connect the device to the PCB is it mounted on.  The end result is a much larger device versus the BGA solution.  All motherboard and graphics chipset vendors utilize BGA packaging with their products now, since the "pin count" is so incredibly high as devices get more and more complex.  If you had to use the old "leaded" approach, a graphics chip would be a huge monster of a part that would be impractical in manufacturing or PCB space. 

The additional real estate that you will gain by going with the TinyBGA module "could" in fact allow you to utilize a large CPU Heatsink that normally encroaches on a DIMM slot but now will clear it over the top of the module.  This is only a possibility.   We weren't able to prove this out and there are lots of different mechanical situations out there but the space savings is only a bonus for you.  Another advantage to the smaller discrete device size on these modules, is that you can build denser modules, 256MB and up, in a smaller footprint.  Here is a shot to illustrate what we mean.

The top module is a Double Sided 256MB DIMM with 32 chips and the bottom is a 144 pin S0-DIMM (small outline DIMM).  

From an electrical spec point of view, the TinyBGA DIMM has several advantages due to the implementation of the BGA packaged SDRAM chips on board.  BGAs have inherently better noise characteristics, signal integrity and thermal efficiency, versus their TSOP or leaded counterparts.  The following charts, courtesy of Kingmax, illustrate the benefits pretty well.

Noise of characteristics of TinyBGA Versus TSOP SDRAM

In these images, the light blue line indicates noise relative to the clock, in yellow.  Notice that the line in the TinyBGA shot has very little skew and jitter against the base line.  Furthermore, the red line indicates the clock rise and fall times. As you can see, the Tiny BGA has a much more organized appearance indicative of a cleaner signal.  Overall, the TinyBGA has significantly better signal integrity versus a TSOP package.

With respect to heat dissipation, the TinyBGA is superior as well.

The average surface temp of the TinyBGA is 93.9 versus 102.2, although we are not told at what frequency the chips were being run, in this shot.  At any rate, it is widely known that BGA devices dissipate heat better than leaded devices, so we'll take their word for it.

 
Due to the obvious advantages of the BGA package, in theory, the TinyBGA module from Kingmax should be able to perform better than any TSOP based module on the market, right?  Well, that's the heart of the matter isn't it?  Let's find out...
 

Performance and Stability

 

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