资料介绍
如何降低同步轉換噪聲How to Reduce the Simultaneous Switching Noise
From the former lecture notes- Introduction of Simultaneous Switching Noise and The Effect of Loading Conditions on Simultaneous Switching Noise , we can know that if the NMOS transistor stayed in saturation through the transition of the input, the maximum simultaneous switching noise can be obtained as: VKtr é 4VDDnLK ù (1) Vnman = VK + ê1 1 + 2VDDnLK tr where VK = VDD VT . Now we want to study the factors that influent the magnitude of simultaneous Fig. 1. Maximum SSN versus number of drivers at C L = 15 pF
3 2 .5 Maximum SSN (V) 2 1 .5 1 0 .5 0 0 20 40 60 80 100 N u m b e r o f s w i tc h in g d r iv e r s
Fig. 2. Maximum SSN versus LVSS at C L = 15 pF and n = 4
3 Maximum SSN (V) 2.5 2 1.5 1 0.5 0 0 50 Lvss (nH ) 100 150
switching noi
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