Basic features of IC-EMC

The tool IC-EMC is able to perform comparisons between measurements and simulation of conducted, radiated emission, near-field emission, S and Z parameters, immunity and signal integrity, as illustrated below. Moreover, it includes also different tools to build models of IC package, PCB traces and cables.

Presentation of the main features.

The general simulation flow with IC-EMC is reported below. The process starts with the edition of the circuit schematic. Component models are provided by IC-EMC or external libraries. The netlist file generated by IC-EMC serves as input file for SPICE simulator. IC-EMC is compatible with two free SPICE simulators: WinSPICE, LTSPICE and Ngspice . At the end of the simulation, SPICE results are exploited by IC-EMC post-processing tools. Different measurement file formats can be imported to compare simulation and measurement results and tune simulation models.

The schematic editor enables building the EMC model of the integrated circuit. IC-EMC contains a palette of symbols (R,L,C, TLines, sources, probes, active devices, etc..), situated on the right of the screen, as well as some basic editing icons.

IC-EMC eases the comparison between measurement and simulation of parasitic emission such as the case study reported below concerning the S12X microcontroller (see application notes). The predicted emission level fits quite correctly over the critical bandwidth 10 MHz-1 GHz. The electrical model used for this simulation is closely related to physical parameters, the internal current source is simply modeled as a triangle.

IC-EMC includes a field solver coupled to an IBIS-based 3D construction of the package to simulated all components of the electrical and magnetic field. A comparison between XML measurement and simulated field mak be obtained as illustrated below (S12X project, see the application note of this case study).

Impedance identification is handled by IC-EMC to construct the passive distribution networks of ICs for future emission and immunity prediction. [S] parameter measurements can be downloaded and fitted with Z(f) profiles obtained from AC simulations.

The immunity prediction is one of the most ambitious and innovative module in IC-EMC. A full model of the RFI source generator, amplifier, coupler is provided. Examples of direct power injection models dealing with boards, connectors and IC package input pins are provided, as well as non-linear structures of I/O and supply rails (see application notes). The susceptibility simulation is automatically controlled by a specific RFI interface menu shown below. The RFI window enables to select the desired frequency and amplitude sweeping for the RFI, extraction of power and display according to measurements.

The main commands of the tool are, from left to right: the Spice simulation icon translates the schematic diagram into a SPICE-compatible text file, the other icons give access to the emission spectrum window, the impedance vs. frequency, the immunity simulation screen, and the near-field simulation screen. The same icons are accessible using the "EMC" menu as detailed below.

In IC-EMC, specific tools are also provided for various aspects of integrated circuit characterization, as well as simple screens to ease data conversion, resonant frequency evaluation, interconnect R,L,C evaluation, and access to advanced tools sur as the 3D package viewer, the attenuation in cables, IBIS, etc... The "tools" sub-menu is detailed below.