SDRAM stable ?

Hi All,
Do you ever experience SDRAM not stable in mass production?

Best regards,
Boki.

 

Never used the stuff myself ( except in my PC of course ).

I expect that means you have a problem ? I'd expect you need to look at
timing issues maybe.

Did you finally manage to work out the volts and amps needed to produce 1
watt in an 8 ohm speaker btw ?

Graham

 

ya ... timing... but seems in a correct range...

For speaker problem, I remember I had ansewrd you alrady, isn't it ?
http://groups.google.com.tw/group/sci.electronics.design/msg/110b2d35c8ec6ec9?hl=zh-TW&


Best regards,
Boki.

 

I have never had issues with SDRAM or DDR that was in production in the
last 10 years or so. Of course, if you are buying from a 're-labeller',
your results may vary.

My experience is for units in production (still are as far as I know, 6
different products, multi source parts) with >100k parts per year for
SDRAM and >500k parts per year for DDR.

A re-labeller is a nice name for an outfit that takes known bad batches
of parts, re-labels them and then sells them.

Cheers

PeteS

 

Thank you very much for advice.

I am still finding the problems...

Best regards
Boki.

 

I have find out the root cause, when we add bead for EMI / ESD, we
increase the rising / falling time on SDRAM data pin.

I remember the ESD test will fail when the ESD test signal comes from
memory card slot(so we add those beads/resistors), but I can't sure
they are for EMI or ESD.

btw, the problem is timing, but it seems that do not to change the
layout now, or we have to re-test the EMI/ESD/XXX/@@@, how do you think
change a high speed SDRAM directly? any other ideal?

Thank you very much!

Best regards,
Boki.

 

ha, that project is running again.