Comparison of EMI effects on different current mirror structures using a post-processing framework

In this paper the use of a simulation framework for comparing the effects of electromagnetic interference (EMI) on different current mirror structures is demonstrated. This is done with the help of an existing tool that is extended by specific, newly developed Python^® scripts. The Cadence Design System and Spectre are used as simulation environment. The resulting outputs obtained by DC and transient simulations serve as an input for the next post-processing steps. The investigated current mirror topologies are well-described in literature and are already analyzed with respect to their EMI robustness. This paper focuses on simplifying the comparison of these structures and reducing the need of mathematical derivations. The script results are displayed directly in the schematic by using a heatmap and annotations for voltage nodes and current terminals. Mainly, two analyses are performed, whereas one part deals with EMI-induced DC offset shifts and the other part deals with the propagation of disturbance frequencies to the output current. Finally, the analytic results are compared with the graphical ones in order to check the feasibility of using the presented framework and the newly developed scripts and procedures.