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各位：
DM8168 ddr的VTT为什么是接1.5V呢，谁能帮解释一下吗？图片见附件。
5V电源接到N36 N37，这个电源的上电顺序和其他有什么关系？
图片分辨率太低了，看不清楚。是EVM板的原理图吗？
是EVM板
重新上传了附件。
谢谢！！
是evm板的原理图
已经重新上传附件。
请看下面的FAQ.Q:why is there a low impedance path between EVM_DDR_VTT and EVM_1V5?A:"To keep VTT quiet and stable. The planar DDR3 boards work fine. The reason this is not on DIMM EVM is because VTT was moved to the DIMM."
Shine Zhang 说： 请看下面的FAQ.Q:why is there a low impedance path between EVM_DDR_VTT and EVM_1V5?A:"To keep VTT quiet and stable. The planar DDR3 boards work fine. The reason this is not on DIMM EVM is because VTT was moved to the DIMM."
意思是：EVM_DDR_VTT and EVM_1V5之间是低阻抗吗？
这句话没有理解：The reason this is not on DIMM EVM is because VTT was moved to the DIMM
感谢Shine Zhang的耐心解答。
1. EVM_DDR_VTT 和 EVM_1V5之间有个0.1uf的电容。2. DIMM原理图如下，没用vtt。http://support.spectrumdigital.com/boards/evm816xdimm/revc/files/evm816xdimm_Schematics_revc.pdf
Shine Zhang 说： 1. EVM_DDR_VTT 和 EVM_1V5之间有个0.1uf的电容。2. DIMM原理图如下，没用vtt。http://support.spectrumdigital.com/boards/evm816xdimm/revc/files/evm816xdimm_Schematics_revc.pdf
首先感谢Shine Zhang的回答。
DIMM原理图中将内存放到内存条上（同时VTT也移到内存条上了），不过这好像和我的问题没有什么关系。
我想问的是为什么ddr的VTT通过电容接1.5V滤波。
To keep VTT quiet and stable
Shine Zhang 说： To keep VTT quiet and stable
问题来了，这样做的目的是使得“To keep VTT quiet and stable”，为什么呢？这才是我想知道的。
通常做法是vtt对gnd加电容，而此处是对1.5V加电容，和通常不一样。
