Hi Steve,

have you checked out the SDRAM from samsung?

http://www.samsung.com/Products/Semiconductor/DRAM/MobileSDRAM/MobileSDRAM.htm

I don't know if this is a possebility.

I think 128MByte would be state of the art.

regards

Juergen


Steve Wiseman schrieb:

>Another quandary, chaps. 
>
>To get the power low in Balloon, it's time to start supporting low-
>voltage, mobile-oriented SDRAM. All well and good. However, it's 
>also available in BGA, which would let me save some space - also 
>good. (In fact, quite a lot of space - a TSOP54 package, like we 
>use on Balloon2.0x takes 312mm^2, and an 8x11mm FBGA takes  
>130mm^2. However, you can't stack BGA packages like you can 
>SOP, for the real density obsessives. Current RAM seems to offer 
>up to 256Mbit / package in mobile form, 512Mbit in 'regular' 
>SDRAM. 
>Balloon2.0x allowed us to fill all 4 banks of the SA1110 
>(128MBytes each) for a total of 512MBytes (in theory - I don't 
>think anyone ever built one that massive, did they?). 
>If Balloon3.x only supports BGA packages, it'll be limited to a 
>depressingly low 64Mbytes with current parts. It seems to me that 
>this isn't enough headroom. I could fit 2 pairs of BGA devices, but 
>that seems futile.  - unless we expect the future to bring us 
>mobile SDRAM, in BGA, in 512Mbit or above. Anyone got a 
>working crystal ball I can borrow for a while?
>
>Upshot - I currently favour TSOP 54 packaging, now that mobile 
>die are available in that package. It's not the best of all worlds, 
>but I think the flexibility is handy. Would anyone suggest a 
>different tack? (Socketed memory / SODimms are right out, before 
>anyone suggests it). 
>Note that this doesn't affect the NAND / Boot flash in any way - 
>just because PPC people call everything 'memory' doesn't mean 
>that we have to...
>
>
>Steve
>
>
>
>
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