Where to find Large SRAM

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Can anyone point me in a direction for find a large SRAM chip (>64Mbits) in 16 or 32 bit wide data configurations?

Thanks for your help!

Tim

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w0067814 wrote:
Can anyone point me in a direction for find a large SRAM chip (>64Mbits) in 16 or 32 bit wide data configurations?

Thanks for your help!

Tim

RAM manufacturers' design boards I guess.

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This is a bit large for single chip SRAM devices. The largest I'm aware of is 32Mb from Samsung (2Mx16). You might find some multichip modules that will be this size but you will pay dearly for them.

Dave

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Thanks! I'll take a look. I know it's expensieve but size is everything so the fewer chips the better.

It's such a shame that SDRAM has taken precidence over SRAM. Why are there so few processors out there that can handle SDRAM? :-( I would have thought that with so many ARM processors supporting 64Mbytes of memory there would be more inthe way of large SRAMS.

The other option of course is an SDRAM controller connected to the SRAM port of the processor. Hmmm but how to make such a beast? Time to learn some FPGA stuff.

Tim

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w0067814 wrote:
Thanks! I'll take a look. I know it's expensieve but size is everything so the fewer chips the better.

It's such a shame that SDRAM has taken precidence over SRAM. Why are there so few processors out there that can handle SDRAM? :-( I would have thought that with so many ARM processors supporting 64Mbytes of memory there would be more inthe way of large SRAMS.

The other option of course is an SDRAM controller connected to the SRAM port of the processor. Hmmm but how to make such a beast? Time to learn some FPGA stuff.

Tim


SRAMs have much bigger cells than DRAMs. That results in high capacity SRAMs having impractical die size, which in turn leads to astronomical cost of such chips. Embedding SDRAM controller is much cheaper. And many ARMs have it in fact.

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Thanks for the reply gizmo.

Can you think off hand of any ARM processors that do support SDRAM?

I need to avoid BGA packages so I can hand solder so that limits me in what I can use. Yes there are processors such as the xScale and the AT91RM9200 which have SDRAM interfaces but these are too complex and BGA.

Something more like the AT91R40008 is more suitable, however doesn't have SDRAM capability. I've looked at the Atmel offerings and also the Philips but no joy.

Tim,

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say netsilicon net+50. is an arm7-tdmi and should be available in pqfp. I agree that bgas suck. particularly those with 0.8mm ball spacing.

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ARM's that support DRAM is (amongst others I'm sure), the Sharp LH79520 (a hot deal at about 10$), and the ST STR720 (don't know price yet).
Also, Philips will hopefully add SDRAM controllers to their LPC serie any year now.

For large SRAMS, Digikey have a good deal at fast (10,12,15nS) SRAMS, 256K*16 at about 6$ and Toshiba 512k*16 at 9$.

Larger slower ones, 55-70nS, can be found with Samsung, IDT e.t.c.

But for the REAL big memory, you NEED to use SDRAM.

It's possible to build an SDRAM controller in a simple Xilinx CPLD, but you will have a problem on most ARM derivatives, as they don't expose a WAIT line.

/Jesper
http://www.yampp.com
The quick black AVR jumped over the lazy PIC.
What boots up, must come down.