synopsys 电源总线的分类
时间：10-02
整理：3721RD
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在网上查了些关于电源总线噪声分析的一些文章，大多把总线分成 噪声总线noise power bus 和 quiet power bus，下面是库中的文档说明，这里分3类的power pairs ，有没有高手讲下这三种power pairs的具体区别和用法，查了库文档只有这么点介绍。
The users are strongly encouraged to provide three kinds of power pairs for the CSM35IO122 library. These areI/O , "Core", andQuietpower pairs. I/O power is used by the I/O to switch its external output from one state to the other. This switching generates noise in the I/O power buses on the chip. Core power is used by the core. Quiet power is used by the I/O to sense and suppress switching noise. The best noise suppression is achieved when the Quiet power buses on the chip are free of noise; therefore, separate power pairs for Quiet and Core power prevent the noise in the Core power buses from reaching the Quiet power buses. The users can use the same power pairs to supply both Quiet power to the I/Os and power to the core, but noise performance will suffer. Refer to theSSO GuidelinesandI/O Usage Application notefor more information on the types of power pairs and the numbers of each required.
The users are strongly encouraged to provide three kinds of power pairs for the CSM35IO122 library. These areI/O , "Core", andQuietpower pairs. I/O power is used by the I/O to switch its external output from one state to the other. This switching generates noise in the I/O power buses on the chip. Core power is used by the core. Quiet power is used by the I/O to sense and suppress switching noise. The best noise suppression is achieved when the Quiet power buses on the chip are free of noise; therefore, separate power pairs for Quiet and Core power prevent the noise in the Core power buses from reaching the Quiet power buses. The users can use the same power pairs to supply both Quiet power to the I/Os and power to the core, but noise performance will suffer. Refer to theSSO GuidelinesandI/O Usage Application notefor more information on the types of power pairs and the numbers of each required.
为什么没人理我呢?
还有一种说法是 clear typ（这个不确定） dirty
现在基本能确定了，一般情况下按噪声来分 noise power 和 quiet power ，有的foundry 的库会有不同的设置和要求，比如我上面的库，IO power是受 SSN 影响的power，quiet 是IO PAD的模块中不是SSN影响的power，cell power 就是内核供电，还有的库会把晶振的power也单独分成一种。