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

How to use nmosdnw transistor in layout

Status
Not open for further replies.
M

mahdiiust

Junior Member level 1
Junior Member level 1
Joined
Jan 22, 2013
Messages
16
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,430
Hi
I must connect source and body terminals of all transistor to each other to obtain proper result in hspice.
but when i draw the layout i encountered a problem.
for pmos transistor it's ok because pmos transistors are in seperate wells and i can connect source and body to each other.
but for nmos transistor it's not! :-?
for those nmos transistors which their sources are not connected to Vss, the body is connected to Vss becuase all nmos transistors are in psub.
to solve this problem I try to isolate nmos from psub using nmosdnw transistors. but unfortunately the LVS isn't pass.
is there any important notice in using nmosdnw?I use TSMC0.18rf technology. can somebody help me?
thanks
 

You have to add at the schematic a proper diodes (probably DP and DN) between substrate and bulk of dnwnfet and betweent bulk and vdd.
 
Dominik Przyborowski said:
You have to add at the schematic a proper diodes (probably DP and DN) between substrate and bulk of dnwnfet and betweent bulk and vdd.
Click to expand...

thank you for your answer!
but I can't realize what you mean. schematic.JPGlayout.JPGlvserror.JPG
for example I change my schematic and layout as figures below.
but it's LVS failed!
 

It should be a n-well ring connected to the deep n-well, not just a single contact as in your layout.

In Cadence, I remember there is a switch in the parameter file to turn on the extraction of the well diode, you don't need to add the diodes on your schematics if the switch is not on (default setting off).
 
Thank you very much!
It works!
but how can I draw n-well ring? I use M1_NWELL contact. but it has several DRC error.ring.JPG
 

The layout looks good, not sure what drc errors you see.
 
Should be easy to fix them, check the rules provided by the vendors.

Good luck.
 
Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top