Error in defining width

[AleksandarK]

Hello everyone,

To my understanding, in nazca you can specify the length and width of every cell. So i tried to do the following:

demo.phase_shifter(length=150, width=50).put()

Which returned an error:

…python3.7/site-packages/nazca/bb_util.py”, line 288, in wrapper
cell_new = cellfunc(*args, **kwargs)
TypeError: phase_shifter() got an unexpected keyword argument ‘width’

The reason i want to speficy its width is that it is too wide and would take up too much space in the design with that width, while it can be reduced a lot. Is there a fix for this?

[Ronald]

Dear AleksandarK,

This is not a design “error”, but as Python indicates a TypeError: The phase shifter here does not have a keyword parameter “width”.

In building blocks you basically never set the cell width directly, but possibly other parameters that may affect the cell width.

Note that all interconnects do have a “width” keyword. Hence, if needed, adapt the interconnect to the building block pin width when connecting, e.g. with a “taper” or “ptaper”. See also here

Ronald

[AleksandarK]

In building blocks you basically never set the cell width directly, but possibly other parameters that may affect the cell width.

Okay so i get that.

Note that all interconnects do have a “width” keyword. Hence, if needed, adapt the interconnect to the building block pin width when connecting, e.g. with a “taper” or “ptaper”. See also here

But i dontget this. in my case above, how would i use this? i have to use the cell from demofab, not interconnects. Can you please show how could that work?

[Ronald]

The cell (building block) like the phase shifter is defined by a foundry (in a PDK), you can not change which parameters is has (unless you define your own building block, which may require advanced knowledge of a technology/process). You can change, however, how you connect to a building block.

For an example on connecting (building blocks) see https://nazca-design.org/connecting-to-a-building-block/
For an interconnect taper use e.g. demofab.deep.taper(length=50, width2=3.0).put(...)
A taper has keywords width1 and width2, but if not provided it defaults to the interconnect width.

Ronald

[AleksandarK]

Thank you very much Ronald!

[Author]

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