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标题:
串扰问题？
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作者:
lwenming
时间:
2009-12-21 10:07
标题:
串扰问题？
请问各位大虾，1、HyperLynx对PCB板做快速串扰分析时，需要加入器件IBIS模型吗？2、在加入IBIS模型之后，串扰的值一般是多大，不影响设计？
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我在DXP下面找了个example,对其进行快速串扰分析时，不加如IBIS模型，采用默认的模型参数为
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Board temperature ................ 20.0 degrees C
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Default IC model (used for quick analysis if IC model is missing)
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IC driver rise/fall time ..2.000 ns
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IC driver switching voltage range ..3.00 V
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IC driver output impedance 1.0 ohms
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IC input capacitance ..... 7.0 pF
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串扰门限为
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Maximum allowed crosstalk ........... 200 mv peak
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特定看一个网络：
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NET = SOFT_TCK
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ELECTRICALLY ASSOCIATED NETS --------------------------------------
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None
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AGGRESSOR NETS (Estimated peak crosstalk)
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NetFPGA1S_B22 .................. 233 mv
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Total estimated crosstalk ....................... 233 mv
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** Warning ** Estimate exceeds maximum allowed crosstalk!
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而我分配模型之后，该网络的串扰增加了很多：
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NET = SOFT_TCK
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ELECTRICALLY ASSOCIATED NETS --------------------------------------
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None
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AGGRESSOR NETS (Estimated peak crosstalk)
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NetFPGA1S_B22 ..................1268 mv
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NetFPGA1S_A21 ..................1053 mv
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NetFPGA1S_A20 .................. 456 mv
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SOFT_TDI ....................... 319 mv
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DIG5_SEG2 ...................... 227 mv
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Sum of the two strongest aggressors .............2321 mv
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** Warning ** Estimate exceeds maximum allowed crosstalk!
作者:
kiddguan
时间:
2010-3-30 16:21
需要加入模型，阈值一般可以通过简单计算得到.不同的电平，阈值是不同的，5v的10%=500mv,考虑串扰是500mv的30%=150mv；
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