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
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.