Rules | Recent posts | topic RSS | Search | Register  | Log in

What is the minimun channel length for a CMOS transistor

 
Post new topic  Reply to topic    EDAboard.com Forum Index -> Analog IC Design & Layout
Author Message
Advark



Joined: 22 Feb 2008
Posts: 63
Helped: 1
Location: Lima-Peru


Post25 Aug 2008 16:31   What is the minimun channel length for a CMOS transistor

Hi, can anyone tell me what the minimun channel length for a MOS transistor for AMS 0.35um process, and why follow the LAMBDA rule for width and length for cmos transistor.
Back to top
ytliang



Joined: 04 Aug 2008
Posts: 61
Helped: 5


Post26 Aug 2008 4:13   What is the minimun channel length for a CMOS transistor

If u are using it for low voltage design, I would think 0.35um would be your minimum length??
Back to top
jecyhale



Joined: 19 Feb 2008
Posts: 447
Helped: 46
Location: China


Post26 Aug 2008 8:30   Re: What is the minimun channel length for a CMOS transistor

Advark wrote:
Hi, can anyone tell me what the minimun channel length for a MOS transistor for AMS 0.35um process, and why follow the LAMBDA rule for width and length for cmos transistor.


Usually, 0.35um is the minimum length which is detemined by the process.
Back to top
drDOC



Joined: 17 Jul 2008
Posts: 50
Helped: 6


Post26 Aug 2008 11:01   Re: What is the minimun channel length for a CMOS transistor

Quote:
why follow the LAMBDA rule for width and length


This is mostly layout related. Many conpanies work with a lambda. Minimum lenght is then usually 2 lambda. An designers should always use integer lambda values.

If a newer process comes around you would be able to take the old design and map it onto the new process. This trick usually doesn't work with analog circuits but digital libraries could be mapped from one process to the other. Well at least that's the idea.

Another thing is that layout engineers only see the lambdas and that makes work easier for them. It is easier to always work with a metal spacing of 2 lambda instead of working with a metal spacing of 1um and 0.26um in another project.
Back to top
k_90



Joined: 25 Jan 2006
Posts: 114
Helped: 17
Location: Scotland,GB


Post26 Aug 2008 13:11   Re: What is the minimun channel length for a CMOS transistor

0.35 u would be the smallest transistor length.
Back to top
Advark



Joined: 22 Feb 2008
Posts: 63
Helped: 1
Location: Lima-Peru


Post26 Aug 2008 20:17   Re: What is the minimun channel length for a CMOS transistor

ok, is Lmin= 0.35um and using the lambda rule, Lmin=2Lambda => Lambda=0.35um/2 that would be correct, right ?.
This for layout. The thing is i design a circuit who has all the transistor using the minimun length, why because is for high frequency operation.
Back to top
Loktik_Vitalij



Joined: 15 Aug 2007
Posts: 51
Helped: 12


Post26 Aug 2008 21:59   Re: What is the minimun channel length for a CMOS transistor

>>ok, is Lmin= 0.35um and using the lambda rule, Lmin=2Lambda => Lambda=0.35um/2 that would be correct, right ?.

this is correct
>>The thing is i design a circuit who has all the transistor using the minimun length, why because is for high frequency operation.

for the minimum length of channel - maximum the deviation of the parameters
for the example - NMOS Idsat mismatch



Sorry, but you need login in to view this attachment

Back to top
wanghs1986



Joined: 07 Jan 2008
Posts: 7


Post27 Aug 2008 1:01   What is the minimun channel length for a CMOS transistor

0.35u
Back to top
Post new topic  Reply to topic    EDAboard.com Forum Index -> Analog IC Design & Layout
Page 1 of 1 All times are GMT + 1 Hour


Abuse
Administrator
Moderators
topic RSS 
sitemap