Virtual Ground Fence: A Simple Method for Protection against High Frequency Simultaneous Switching Noise

摘要

When integrating sensitive RF analog devices withcomplex VLSI digital components, simultaneously switchingdrivers cause supply voltage fluctuations which can propagateboth horizontally and vertically between the power/groundplanes. The same voltage source on a printed circuit board canbe shared to increase power efficiency and reduce space used. Inorder to accomplish this, on board filtering is needed to isolatethe noise between these two types of devices for proper operation.Hence, accurate estimation and improvement of the performanceof power/ground planes is critical in a mixed-signal system. Wepresent a new method to minimize the noise transfer at highfrequencies to the power distribution system, called the VirtualGround Fence. At its basic level, the Virtual Ground Fenceconsists of quarter-wave transmission-line stubs that act as shortcircuits between power and ground planes at their designfrequency. We will present various configurations of VirtualGround Fence for different coupling scenarios.