maximum length that can be used in 180nm technology

[jignesh_prajapati]

hi i m designing Rf mixer and using tsmc 180nm, so what is the maximum length that can i use.
and if i m using more than 180nm , suppose 360nm isn't it would become old design?

 

[tadeoman]

I imagine you can use 360nm transistors. I don't know why you say the design is old? Will all your transistors be 360nm, in that case I think you should redesign.

It's ok to have an onversize transistor if you want to limit the current going through that transistor.

 

[dick_freebird]

Maximum gate length may be set by groundrules such as max
length of poly over active (I see 20um in a PDK I'm presently
using, which is not your foundry's but is 180nm node).

There would be no good reason to use such a length for a
mixer. Only for poor-boy high value resistor / low value
current source type uses.