Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

MOSFET W/L ratio and designing 35um technology

Status
Not open for further replies.

ali-

Newbie
Newbie level 4
Joined
Jul 13, 2012
Messages
5
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Visit site
Activity points
1,355
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:
PHP:
#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
Concluded Result.pngSchematic.PNG
 

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..
 

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?
 

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...
 

:D 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?:D
 

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
-
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top