MODELING AND SIMULATION OF COUPLED TRANSMISSION-LINE INTERCONNECTS OVER A NOISY REFERENCE PLANE

A method of modeling and simulation of coupled transmission line inter connects over a noisy reference plane is presented. Limitations in usi ng conventional coupled transmission line simulators to model signal p ropagation over a noisy reference plane are explained. A distributed l umped element circuit model including reference plane parasitics and a ssociated coupling (to signal conductors) parasitics is developed, and verified using SPICE simulations. Inductance and capacitance per-unit -length [pul] matrix elements are calculated using detailed two-dimens ional parasitic extractors, and the partial inductance concept. Result s using this model were compared with conventional ''isolated'' (switc hing noise isolated) coupled transmission line simulations. Significan t differences were found. Package pin placement on the reference plane , and its impact on overall noise characteristics are analyzed.