These screen shots demonstrate how the modelling on the Polar Si8000 offers a significant enhancement over the Si6000 when trying to predict the finished impedance of surface microstrips.

Si6000 and Si8000m coated microstrip models

The following series of pictures shows the differences between the modelling employed on the Si6000 and the Si8000m.

Si8000m Coated Microstrip model — note how the boundary element field solver  takes into account the profile of the solder mask:

Si6000 Coated Microstrip model

Now compare the two predictions for a 75 Ohm trace:

Si8000m enhanced model

The Si6000 calculates 2.4 Ohms low compared with the more accurate model in the Si8000m

Modelling the production process window

Finally, you can also use the Extended Interface Style of the Si8000m to display a process window, and at a  glance see how production process may influence your production yield.

Selecting the Extended Interface Style displays additional fields, Tolerance, Minimum and Maximum so you can specify a range of values for each parameter and observe the effect of manufacturing process variations.

Note the variation in impedance for ± 0.5 mil of etch variation.

Polar Instruments Ltd

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