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.

Register Log in

what length should be used

Status
Not open for further replies.
M

manissri

Full Member level 5
Joined
Apr 16, 2005
Messages
281
Helped
9
Reputation
18
Reaction score
3
Trophy points
1,298
Activity points
3,279
hi i am working on 65nm tech ..
i am designing the opamp and other analog circuit.
my question is what lenght should i take to design the analog circuit.
book told that one should take 2 to 3 times of minimum lenth to avoid channel length modulation.
in 65nm i should take minimum lenght or as book told (2 to 3 times of minimum)
please reply ..
 

for analog design, in general, we don't use minimum length for the considerations of match, gain, etc.
you can comply with the suggestion of book or simulate the characteristic curve of transistors to determinate the length
 

I think 2 or 3um is better for analog block.
 

if its is a switch, you can use the min size.
 

it is not switch ..
it is a complete analog amplfier.
so what length i should use..
 

i recommend you read J. Baker's book - CMOS Mixed-Signal Circuit Design
in this book, author decides the length of MOS by simulating the characteristic curve of transistors
 

i think gingerjiang's method is one of the best methods to determine. We shouldn't always trust what the old books said, as they said from those old days technology, so 2-3 or 4-5 times are enough.
Now, remember, you are using 65um, which is a very very advanced technology which we should take are 2nd or even 3rd effects now, and for leakage issue. Also, i suggest you check the transistor characterization report from foundry, making sure the transistors mismatch is acceptable for your device size., Otherwise, your op-amp will tend to have large mis-match
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top