A method for the optimization of a CMOS driven, center tap terminated (CTT) network in a shared bus design

In this paper, a theoretical method is described for the optimization of a CMOS driven, center tap terminated network. This method is verified by circuit simulations. In the simulations, we have assumed a 70 ohm characteristic impedance of the board interconnects and at the same time, n number of various loads connected at different points on that line. Each of these loads has some stub length that can vary from 1.0 inch to 1.5 inch depending on the packaging technology. The above example is a shared bus situation. This method will also work on other topologies as long as the effective characteristic impedance of that topology is less than Zmin, where Zmin is the minimum characteristic impedance that the CMOS driver can support for a given noise criteria.<>