Parametric Length in Cadence Schematic and Layout

[april1975]

Hello
I have designed a schematic in Cadence composer scematic. I have specified parametric length and width for various nmos and pmos transistors in it. I have analysed the circuit with analog environment. It works. Now I want to design layout of the circuit, I can't generate the layout directly from the schematic, because the length and width are not specified. Is there any way for specifying parametric length in schematic?
april

 

[erikl]

I have designed a schematic in Cadence composer scematic. I have specified parametric length and width for various nmos and pmos transistors in it.
Is there any way for specifying parametric length in schematic?

Seems you already found the solution!?

 

[april1975]

erikl wrote:

Seems you already found the solution!?

yes. In Analog Design Environment, we must add a variable for the length and specify its value. But we can`t generate a layout from the schematic. Because value f length is needed.

 

[erikl]

Sure. But you can still change the length l (and the width w) of individual layout Pcells.
BTW: the parameter f describes the number of fingers in schematics.

 

[april1975]

But now, i think about layout of nmos or pmos transistors in which:
m>1 & fingers>1
How i must draw nwell or pwell? Must nwell be detached for a transistor with separate bulk and source?
How i must path between various part of a transistor?
Do you have any image of layouts for it?

 

[erikl]

But now, i think about layout of nmos or pmos transistors in which: m>1 & fingers>1

For f>1 I think you can use Pcell layout generation. For m>1 you have to parallel m transistors.

How i must draw nwell or pwell? Must nwell be detached for a transistor with separate bulk and source?

This actually is layout basics. Read the relevant books, e.g. Alan Hastings "The ART of ANALOG LAYOUT".

How i must path between various part of a transistor?

By poly (short distances only), M1 and (if necessary) M2 .

Do you have any image of layouts for it?

You can find a lot of layout images in this forum, or in G00GLE images.