MOSFET W/L ratio and designing 35um technology

[ali-]

I try to analyse gm-c filter by HSPICE. Below codes is my attempt to change the attached schematics to the SPICE codes with regard to MOSFETs W/L ratio as presented:

M1, M2 10/1
M3, M4, M5 M8 4/1
M6, M7 8/1
M9 16/1

At first circuit is supposed to be designed on the 35um technology, so I choose one of the mosis model from https://www.mosis.com/cgi-bin/cgiwrap/umosis/swp/params/tsmc-035 the first one and then I put it in the file to be used as model file for SPICE analysis.
my question is that
-How can we calculate the MOSFETs W,L with these ratios in 35um technology?
-Dose the HSPICE code and circuit match?
-what about the calculation of the gain for gm-c Filter and input voltage of differential circuit(only 180 degree different in phase)?
-and the last question, is it right to connect vin- and vin+ sources lessen polarity to the vss? or they must be connected to the Node 0(Ground)?

thanks:wink:

#OTA# 
.OPTION POST accurate 
.op 
.ac dec 10 1 100G  
.probe ac gain=par('(v(out)/(v(7)-v(6)))')
M7 2 1 9 9 cmosp W=8U L=1U
M4 1 1 9 9 cmosp W=4U L=1U
M3 4 4 9 9 cmosp W=4U L=1U
M6 out 4 9 9 cmosp W=8U L=1U
M2 1 6 3 10 CMOSN W=10U L=1U
M1 4 7 3 10 CMOSN W=10U L=1U
M8 2 2 10 10 CMOSN W=4U L=1U
M5 out 2 10 10 CMOSN W=4U L=1U
M9 3 8 10 10 CMOSN W=16U L=1U
Vin+ 7 10 DC 1 ac 0.7 
Vin- 6 10 DC 0.7 ac 0.7 180
Vbiass 8 0 DC -1 
Vss 10 0 DC -1.65
Vdd 9 0 DC 1.65
c1 out 10 50pf

.inc 'cmos.txt' 
.end

 

[graphene]

can you be clear with you questions.. how can we calculate W, L ??? its confusing..

. i think you can configure this in your schematic design and then generate a automated netlist from the schematic which will avoid the confusion w.r.t the code and circuit..

 

[ali-]

I asked some question which are seprated by '-' one of them is that how can we determine the width and lenght of the MOSFETs with these ratios with respect to 0.35um technology?

 

[graphene]

well dats understood... but again your question is confusing... how to determine W,L ? you need to check the scematics if u have one or again as u may have from netlist infer it...
.
irrespective of any technology the W,L determined will be the same...

 

[ali-]

I'm pretty konw in this topic, the only things that I have are presented in the first post, For example, if w/L=8/1 is it right to choose 0.35um for L and 0.35um*8 for W ?(Do I have any limitation)
and other questions are still remained?

 

[graphene]

NO there is no such limitation... the minimum length should be 0,35 and dats it.. you can tailor it in any way you want.. no restrcitions unless stated from your project...
.
for code match insufficient information.. well you shall better present thigns so that either party doesnt waste time..
.
wat tool are you using.. how do u draw your schemeatic ??
.
Step 1.. draw your schemtic... from simulation environment, such as ADEXL in Cadence Virtuoso generate netlist... it would certainly be the same.. dats better than wrting them on yr own..

- - - Updated - - -

write and read the question as if anyone can understand and then post with sufficient infos.. ... despite having so many views for you Post , dats why, though a simple topic ppl dint reply and waste thier time... sorry but not to hurt you be specific so that one who wants to help doesnt run away...
.
3rd question i think some more information needed... !!!!!!

4th ideally Ground should be conencted unless in specific situations..
.
All the Best
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