Hi everyone, In skywater 130nm pdk, are mismatch coefficients of process parameters such as A_{vth}, A_{\delta_R/R}, A_{\delta_C/C} available? If so, where can we find those mismatch coefficient values?

I don't think these values are published anywhere so you would have to find them in the parameter files. See, for example, in the open_pdks install,

libs.ref/sky130_fd_pr/spice/sky130_fd_pr__nfet_01v8.pm3.spice

. At the top of this file, there are mismatch parameters in Spectre syntax, e.g., :

* statistics {
*   process {
*   }
*   mismatch {
*     vary sky130_fd_pr__nfet_01v8__toxe_slope_spectre dist=gauss std = 1.0
*     vary sky130_fd_pr__nfet_01v8__vth0_slope_spectre dist=gauss std = 1.0
*     vary sky130_fd_pr__nfet_01v8__voff_slope_spectre dist=gauss std = 1.0
*     vary sky130_fd_pr__nfet_01v8__nfactor_slope_spectre dist=gauss std = 1.0
*   }
* }

These have been commented out because they are not compatible with ngspice. What has been done during the open_pdks installation is that these parameters in the models have been converted to ngspice syntax, such as this one (note that the name of the coefficient is just the name of the Spectre gaussian parameter without the "_spectre" suffix):

+ vth0 = {0.49439+sky130_fd_pr__nfet_01v8__vth0_diff_0+MC_MM_SWITCH*AGAUSS(0,1.0,1)*(sky130_fd_pr__nfet_01v8__vth0_slope/sqrt(l*w*mult))}

You can infer from this that the coefficient of mismatch is

sky130_fd_pr__nfet_01v8__vth0_slope

. This value can be found in

libs.tech/ngspice/parameters/invariant.spice

:

+ sky130_fd_pr__nfet_01v8__vth0_slope = 0.003356

Sorry there's not a more convenient way to get this information. The files should be parsed for this information and the values published in a table along with the rest of the documentation.