transistor fingering

[Junus2012]

Desr friend

what is the difference between the M (multiplecation factor ) and the fingering

I have used the M, its like parallel transistor equivelant for one transistor and it has a big advantage on circuit layout matching

but the fingering i didn't use, however my teacher told me that is used in the RF design but I dont know much about it

kindly if you have any material about this topic it will very helpful for me

Erikl are you here ??, the Wochenende is vertiche

 

[erikl]

... if you have any material about this topic it will very helpful for me

See here: View attachment Analog_Layout_Techniques_in_VLSI.pdf. Search for fingers.

 

[Junus2012]

Thank you very much Erikl
have a nice night

 

[jgk2004]

Another important note, without having to read the pdf, a fingered device shares sources and drains, therefore it has less capacitance and is faster in terms of fT. Additionally, they take up less area then multiples. The way I see it, if you want better matching at the price of area, you use multiples. If matching can be relaxed, then use fingers for increased speed. If you don't care about matching, area, or speed, flip a coin and pick one..

Just my 2 cents,
JGK