Friday, April 1, 2016

Making Parametric RF layouts in Cadence (Pcell)

Once you are done deciding the inductor values for an RF design, you can directly generate a layout in Cadence. The library you use may generate either a rectangular or an octagonal inductor. The same can be calculated using any of the calculators available online.

Using the value you desire and the calculator that calculates inductance using the dimensions, you can enter the same in Cadence while selecting the instance as shown below.

Creating an instance by entering values

You will see a parametric cell block in the layout window for the same. To descend into how does your inductor unit cell look like, go to Window -> Hierarchy -> Descend Edit. To convert the block into layout, press Shift+f.

Menu to descend in to the hierarchy

Ignore all warnings and errors. You will see a layout as below. The blue layer is the inductor and the green crossed square is the metal in the other layer used to extract the terminal inside the loop. The same works for resistors, MIM capacitors and transistors.

The generated layout of the inductor