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.

Length of transistors in Layout

Status
Not open for further replies.

Shady Ahmed

Member level 5
Joined
Jan 26, 2013
Messages
86
Helped
2
Reputation
4
Reaction score
2
Trophy points
1,288
Activity points
2,041
I am only used to designing in the schematic view without expecting the designs to be fabricated.

Now i am designing a chip to be fabricated, so , i am asking for some tips in schematic design that would help and make life easier in Layout and packaging phase, what to do and what not to do?

For instance: i heard that i should use the same transistor length for ALL MY DESIGN , otherwise it would cause troubles in layout phase? is that true?
 

erikl

Super Moderator
Staff member
Joined
Sep 9, 2008
Messages
8,112
Helped
2,694
Reputation
5,368
Reaction score
2,293
Trophy points
1,393
Location
Germany
Activity points
44,062
i heard that i should use the same transistor length for ALL MY DESIGN , otherwise it would cause troubles in layout phase? is that true?

Not at all. Use the transistor models provided by the fab, and assign widths and lengths as you need. Depending on the models there will be min. and max. limits for both width and length for every model. If you need more than max. limit, parallelize (width, e.g. by fingering) resp. serialize (length) the devices.
 

Shady Ahmed

Member level 5
Joined
Jan 26, 2013
Messages
86
Helped
2
Reputation
4
Reaction score
2
Trophy points
1,288
Activity points
2,041
Ok, thanks for the help.

Any other layout tips ?

for ex: the feasible values of resistors and capacitors that i should stay within in the schematic such that it doesn't take up a large area on the layout?

Any thoughts are much appreciated.
Thanks for your time
 

erikl

Super Moderator
Staff member
Joined
Sep 9, 2008
Messages
8,112
Helped
2,694
Reputation
5,368
Reaction score
2,293
Trophy points
1,393
Location
Germany
Activity points
44,062
Any other layout tips ?

for ex: the feasible values of resistors and capacitors that i should stay within in the schematic such that it doesn't take up a large area on the layout?

Resistors: this depends on your process. Usually between 103 (l/w >≈ 1) and 106 Ohm (area consumption).

Capacitors: also process dependent (availability of double poly, MIM). Usually 10-14F ( > parasitics) - 10-12F (area consumption).
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top