IBIS中的Rref和R_fixture有什么区别？

格林杨 · 发表于 2013-11-26 10:32

研究过IBIS的大牛们，IBIS中的Rref和R_fixture有什么区别呢？网上找了些材料：Rref：Test load applied to the output that the semiconductor vendor uses to define timing such as propagation delay and/or output switching time of the model. R_fixture: describe how the buffer was loaded when generating the waveforms. These numbers are useful in calculating the current during HIGH to LOW or LOW to HIGH transitions. 看了之后感觉还是不理解，总感觉两个东西是一样的。测量Propagation delay 与上升沿下降沿的测试阻抗为啥要不一样呢？求解答。