Well Samsung obviously have 512M parts in BGA, so given the current
memory area on Balloon 2.0x of 594 mm^2 (measured from the board) then
BGA packages at 130mm^2 (from Steve's e-mail) we can get four in, with
room to spare. This gives us 256M.
On the assumption that there are common footprints to the 256M parts
then we may start out with 128M and grow to 256M. That's twice what we
currently have and a potential for four times what we currently have. It
also gives a nice cost down option of only fitting two 256M parts to
give 64M, something we've been saying should be available for the
educational end of the market.
Given that:
a) Most of us have lived happily with 64M (even TCL).
b) No one has owned up to ever having stacked up TSOP's, something you
could only do on a few "one offs" given that it wouldn't reflow.
c) You can only work within the technology available at the time of
design.
I'd say the choice was obvious go for 4 BGA's. Stacked TSOPS is nice and
macho but not a practical solution to churning out a few hundred a week.
If you really want 1G then design and build an expansion board via the
LoonBus (it needs a name...) OK so it will be slower, but the capability
is there (I assume).
Cheers
David.
-----Original Message-----
From:
balloon-admin@balloonboard.org
[
mailto:balloon-admin@balloonboard.org] On Behalf Of Steve Wiseman
Sent: 06 October 2004 18:45
To: freesurf
Cc:
balloon@balloonboard.org
Subject: Re: [Balloon] Balloon3 - how much RAM?
06/10/2004 17:52:05, freesurf
<
juergen.messerer@freesurf.ch> wrote:
>Hi Steve,
>
>have you checked out the SDRAM from samsung?
>
>http://www.samsung.com/Products/Semiconductor/DRAM/Mobil
eSDRAM/MobileSDRAM.htm
>
>I don't know if this is a possebility.
It's all in BGA, fineline-bga or teeny-tiny chipscale BGA,
unfortunately. Micron are thr first people I'd met offering mobile
SDRAM in the SOP package. Before I found those, though, I thought
we were really stuck, with only the BGA option, which does seem
to limit us as to size (more because we can't stack them.
However, at least Samsung seem to be supporting 512M in low
voltage - Micron say 'obsolete' - which is a bit odd...
>I think 128MByte would be state of the art.
Does that mean you think 128MBytes is as much as you could ever
want, or as much as you think we can fit?
Are there any big memory users out ther considering Balloon
(other than TCL, who seem to want as much memory as humanly
possible, and tehn a bit more :)
Steve
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