Instance length does not fit the given lmax-lmin

[cherryic]

does not fit the given lmax-lmin

Hi all,

I need to use some PMOSFETs which have a length of 40u, but in the .scs file provided by TSMC, the length can not be larger than 20u, so I modify the lmax=20u to 50u in the file. But, when I simulate the circuit in Spectre it still says: “IXX.MXXX: Instance length or width does not fit the given lmax-lmin or wmax-wmin range for any model in the ‘pch’ group”, what should I do to solve this problem? Thank you in advance.

Best regards,
Terry

 

[cherryic]

spice model lmax lmin

Can someone help me?

 

[cherryic]

lmax mos spectre

Any ideas?

 

[hdqkwr]

spectre lmax-lmin or wmax-wmin

Hi cherryic,you can use m(multiplier) together with w to represent your width,
say m=4 w=10u to represent w=40u.You should not modify the model.

 

[pbs681]

error & hspice lmax/lmin range

Hi all,

I need to use some PMOSFETs which have a length of 40u, but in the .scs file provided by TSMC, the length can not be larger than 20u, so I modify the lmax=20u to 50u in the file. But, when I simulate the circuit in Spectre it still says: “IXX.MXXX: Instance length or width does not fit the given lmax-lmin or wmax-wmin range for any model in the ‘pch’ group”, what should I do to solve this problem? Thank you in advance.

Best regards,
Terry

Are u using binning model? If yes, pls make sure u change the correct bin. There will be a few bins inside with L=20u.

 

[Blackuni]

lmax/lmin hspice

Hi,

1. Which Process/foundry?

2.Its normally not recommended to edit model library.

3. If you are doing it for trail purpose then quick solution would be :- remove the Wmin,Wmax & lmin, Lmax value from the model card. This will make spice to simulate the MOS with W & L values given in MOS instantiation. (U should not be doing this if u r sending u r design 2 fab)

4. if u r using foundry library then, MOS devices will be grouped in bins(somthing lik th 1 in FFT , Grouping based on min, max W & L). Make sure both W & L u use MOS instantiation falls into any 1 of this bins(normally there will b 12 bins for each mos). Error will be reported if spice is not able put the mos in any bin. This may happen becoz of W r L


5. If u r process don't support u r L directly thn go for alternate configuration( 2 devices D G SD G S ( but i never used this


Hope this helps.

Thanx,