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[SOLVED] stupid question about resistor in integrated circuits

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nanock

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Hi friends,
Is it possible to create a 20k or 30k or even 50k resistor in an IC,I mean op amp?
kind regards,
 

srizbf

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it is possible.
but , what about the area reqd for resistor( that is , realestate area)
one can make many many active devices in one resistor space.
 

keith1200rs

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You can make any value you like within reason, but as suggested - it takes area. I have used 200k resistors and have seen resistors of several Meg ohms used. Using high resistance polysilicon layers they aren't too large although it depends on the process, design rules, tolerances etc. Some processes have very high resistance layers with 10k ohms per square so 1M is only 100 squares.

Keith.
 

ken_cn

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I think 50k is very easy to realize by using a ploy resistor.
 

qwertyuiop415263

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we can make resistors in IC. In 90nm technology resistivity of 1 NMOS is 7 ohm (approx). if you want to make resistance of 10k then you have to use 1428 NMOS transistors which obviously take more area. So usually we avoid resitors in Integrated Circuits while designing.
 

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