Hello again! Since no-one answered, I re-send my question, in case there was some problem which prevented many of you from seeing my question. Thanks again Itzhak ________________________________ From: Hirshtal Itzhak Sent: Monday, March 22, 2010 3:49 PM To: si-list@xxxxxxxxxxxxx Subject: DDR3 VTT Accuracy Requirements Hello, I've noticed lately that VTT specification for the DDR3 SDRAM devices is not defined as was VTT for DDR2 devices. For the DDR2 devices it was required to be no further than 40mV from VREF. In the DDR3 spec this requirement has been removed and instead a note says that the MIN & MAX values for this supply are system dependent. What system considerations are to be applied for VTT tolerance? The only thing that comes to my mind is the timing of the ADR/CMD signals. Would simulations with the "skewed" VTT be enough to evaluate the impact of certain VTT in-accuracies? Can I assume (as a 1st degree assumption) that the in-accuracy of VTT will be directly reflected in the threshold levels of the device? And are there other considerations to be taken? Thanks in advance Itzhak Hirshtal The information contained in this communication is proprietary to Israel Aerospace Industries Ltd., ELTA Systems Ltd. and/or third parties, may contain classified or privileged information, and is intended only for the use of the intended addressee thereof. If you are not the intended addressee, please be aware that any use, disclosure, distribution and/or copying of this communication is strictly prohibited. If you receive this communication in error, please notify the sender immediately and delete it from your computer. Thank you. This message is processed by the PrivaWall Email Security Server. ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List technical documents are available at: http://www.si-list.net List archives are viewable at: //www.freelists.org/archives/si-list Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu