Hi there community.
I have a doubt regarding the multiplier parameter on the MOSFET properties.
In a book that I have they say that if we have a big transistor we can split him several gates (fingers) and then place them together. Thinking with m=1 (multiplier), I would say that I would instantiate a mosT with W=1000um with number of finger equal to 10. That would translate into 100um per finger times 10 equals 1000um.
Now, if I want a device with a width of 2000um, I should use a W=2000um and 20 fingers? With m=1 or I should use a W=1000um with 10 fingers and m=2?
I have done a small test using the above mentioned parameters. When I use a multiplier of 2 the Layout XL generates two transistor with the same W, L and number of fingers.
I read in here: http://citeseerx.ist.psu.edu/viewdoc...=rep1&type=pdf (page 34) that the width of the transistor is: "Describes the width of each MOSFET finger. Total Device Width = Width * Number of finger * Multiplier", however it says at the same time that "“Number of Fingers” and “Multiplier” differ in simulation but are interpreted the same by this program. “Number of Fingers” implies merged sources/drains while “Multiplier” does not imply sharing. It is recommended that the user only change the “Number of Fingers” field so that layout and simulation will more closely match."
I don't know if this is a reliable source, but I couldn't find any useful information on the web, even in here, the Cadence forum community website.
Just for the record: here: http://www.designers-guide.org/Forum...num=1351774957 the guy says that when he uses other multiplier value (16) when he does the LVS it gives an error. I didn't understood if it might have something to do with the multiplier or he must be doing aome kind of mistake.
What I intend is to know which one of these parameters is better to use, multiplier or fingers for the better sizing of MOS?
I am confused!
Kind regards and thanks in advance.
I have a doubt regarding the multiplier parameter on the MOSFET properties.
In a book that I have they say that if we have a big transistor we can split him several gates (fingers) and then place them together. Thinking with m=1 (multiplier), I would say that I would instantiate a mosT with W=1000um with number of finger equal to 10. That would translate into 100um per finger times 10 equals 1000um.
Now, if I want a device with a width of 2000um, I should use a W=2000um and 20 fingers? With m=1 or I should use a W=1000um with 10 fingers and m=2?
I have done a small test using the above mentioned parameters. When I use a multiplier of 2 the Layout XL generates two transistor with the same W, L and number of fingers.
I read in here: http://citeseerx.ist.psu.edu/viewdoc...=rep1&type=pdf (page 34) that the width of the transistor is: "Describes the width of each MOSFET finger. Total Device Width = Width * Number of finger * Multiplier", however it says at the same time that "“Number of Fingers” and “Multiplier” differ in simulation but are interpreted the same by this program. “Number of Fingers” implies merged sources/drains while “Multiplier” does not imply sharing. It is recommended that the user only change the “Number of Fingers” field so that layout and simulation will more closely match."
I don't know if this is a reliable source, but I couldn't find any useful information on the web, even in here, the Cadence forum community website.
Just for the record: here: http://www.designers-guide.org/Forum...num=1351774957 the guy says that when he uses other multiplier value (16) when he does the LVS it gives an error. I didn't understood if it might have something to do with the multiplier or he must be doing aome kind of mistake.
What I intend is to know which one of these parameters is better to use, multiplier or fingers for the better sizing of MOS?
I am confused!
Kind regards and thanks in advance.