Hello all, Recently I was trying to create a symbol for a transmission gate circuit, I wanted the sizes of the PMOS and NMOS to be a design variable in the circuit. I followed the tutorial guidelines but there is still a problem. It looks like the widths of p and nmos are called ‘w’ and lengths are called ‘l’ for both, when I try to add the following in the symbol

WP=@WP WN=@WN LP=@LP LN=@LN

it doesn’t work I think because the widths and lengths aren’t WP and WN they’re simply w for both. If anyone can help, I’d be very thankful.

there is a parametric pass gate in the example circuits:

sky130_tests/passgate.sym

or

sky130_tests/passgate_nlvt.sym

. The manual here explains in detail the steps. In the passgate example i have created 4 parameters: W_N, W_P, L_N, L_P. I don't use WN/WP/LN/LP since ngspice confuses LN with the logarithm function. In the underlying schematic you must use W_N/W_P/L_N/L_P for the transistor sizes.

Thanks, Stefan.