How to make resistor in Magic layout

[smoglu]

Hi. I am taking a CMOS analog design course and in course project I need to submit layout of my design, using Magic. Then I need to extract .spice file using
extract
ext2spice
commands and simulate .spice file in LTSpice. I have a 100 ohms resistor in my circuit and I cannot implement it in Magic. I tried things like metal1 and also rmetal1 but none of them worked. Can anybody show me how to implement a resistor, and do I need any extra commands to extract it to spice file? Thanks in advance.

 

[srizbf]

metal1 or metal2 is not for resistance.

use the sheet resistance of n material and calculate the
area reqd for 100ohms. select the suitable l and w .

draw it in magic .
since magic has online drc check and adjust it.

then extract the spice netlist.

srizbf
5thmay2010

 

[smoglu]

Thanks for reply.
My problem is, even though I put a material to get a resistor, I cannot see it in spice files. Maybe I don't connect it properly. Does magic interpret the circuit depending on what layers we use?
Anyway, can you give me more information? I still cannot do this.
Edit:By the way, Do you mean some layer by sheet resistance? I don't have such a layer

 

[srizbf]

if you have drawn properly ,
then magic will definitely spice it.

-Does magic interpret the circuit depending on what layers we use?

irrespective of layers , if , there is a connection ,
then no problem .

-Do you mean some layer by sheet resistance?

no layer...

refer vlsi book for getting the concept of
sheet resistance .

srizbf
5thmay2010

 

[sree_lakshmi]

You can try using nwell or poly inorder to get resistance.
create a layout for resistor and also spice for R=100ohm and run lvs keeping A & B as pin names for resistor ends(both in schematic and layout).
You can get the resistance value from the lvs report. ( it will show parameter error and resistance value)
go through design rule document for approximate sheet resistance.
BTW u need to use resistor layer in order for the tool to recognize it as a resistor.

Regards,
Sree

 

[Somashekhar]

Hi,

U can use poly for making the resistor in MAGIC, to identify the poly as resistor u have to put a pseudo layer. Pseudo layer name is pseudo rpoly.

Give two terminal names then extract you will get the value of the resistance between the nodes.

If u need i will send you scipt that generate the required resistance value using the POLY.