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What ever happened to BGA memory?

Last response: in Memory
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February 7, 2006 4:31:08 AM

Remember like 4-5 years ago everyone said that BGA memory would take over the world? What the hell happened? The only place I see BGA memory on anything is video cards. I have seen a few BGA DIMMs, but that was a while ago. Anyone care to speculate?

-mpjesse

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February 7, 2006 5:29:34 AM

its probably cos BGA rams dont yield as well as the normal TSOP and hence not exactly profitable to do that

i would think it might come back again with DDR2

just my opinion

edit: i thought the so-dimms are already using BGA? no?
February 7, 2006 5:59:49 PM

All the so-dimms I've ever seen are TSOP. But I don't deal w/ laptop memory that often so I'm not exactly an authorative source.

I remember reading that BGA memory was actually supposed to make manufacturing costs lower.... I guess not though.

-mpjesse
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February 7, 2006 9:06:18 PM

That stuff is frigin cool... never even heard of that before.

-mpjesse
February 7, 2006 9:27:31 PM

Umm...don't know if you can still get it, but here.
February 7, 2006 10:27:24 PM

Good point.

Speculating (!), with so many new technologies 'threatening' the market (FB-DIMMs [BGA?], MRAM, CNT, F-RAM, etc), which might also bring new packaging approaches, manufacturers may just be holding on to the price/performance ratio TSOP ('Thin Small Outline Package', for those who are wondering...) allows, considering how highly lucrative (& speculative!) RAM business is. Why TSOP (yet)?
Still speculating, i don't see how BGA can be a cheaper solution to TSOP (just as i don't see LGA being cheaper than PGA...), for two main reasons: first, [RAM] memory density has grown no-where near GDDRx (which, unlike wusy 'said', is made of very stable, fast BGA chips; that's why they're used in graphics; older, slower graphics memory chips, are also TSOP); second - as absurd it might seem (seems to me!) - it may have to do with chip... geometry! See, when scaled down, rectangular chips maintain a better ratio between linear (TSOP 'legs') and areal (BGA 'balls') than square chips; hence, for the same constant ratio, there can be put more 'legs' around a rectangle than around a square. If chip density & pin-count, EMI & bus specs, for instance, are no-issues, than why not to stick with TSOP (even if it brings less reliability than BGA)?

Maybe - aside production costs - these "reasons" are also behind, in more than one way, of the WLCSP (of which i didn't have a clue!) abandon...


Again, just speculating!


Cheers!

P.S.: Although wusy was referring to DDR BGAs while i was referring to GDDR BGAs, i still think the same "reasons" apply.
February 7, 2006 10:41:34 PM

Again, all FB-DIMMs i've seen so far (in pictures), were BGA...
!