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.

Is it possible to use a resistor 1.8M ohms in TSMC 180nm?

Status
Not open for further replies.

anhnha

Full Member level 6
Joined
Mar 8, 2012
Messages
322
Helped
4
Reputation
8
Reaction score
4
Trophy points
1,298
Activity points
3,684
Hi.

I am wondering if it is possible to use a resistor 1.8M ohms in TSMC 180nm.
Is it too big?
Thanks.
 

I'm not familiar with TSMC 0.18 but if You have hi-resistivity polysilicon or well resistors available with sheet resistance around 1-2k\[\Omega\]/square it still will be possible, but!

1. Assuming minimum width of resistor (e.g. 0.3um) and 2k\[\Omega\]/square You will need resistor with W/L=0.3um/270um with probably very bad matching or 1um/900um with better expected parameters.
2. Assuming 0.5fF/um^2 of parasitic capacitance to subtrate You get approximately 75fF for 0.3/270 and as high as 450fF of parasitic cap.

So the question is why do You need 1.8M\[\Omega\] resistor and why don't use a proper biased transistor?
 
  • Like
Reactions: anhnha

    anhnha

    Points: 2
    Helpful Answer Positive Rating
Thank you. I need the resistor for biasing circuit for my LDO.
Could you tell me how to make resistor from transistor?
 

I assume that You want used this large resistor to set current in current mirror?
If yes, the better choice is to design some kind of widlar source or other biasing circuit which is immune on supply changes.
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top