Q- factor enhancement in active inductors

[vinogunasekaran]

hi, I am trying to design an active inductor with a high quality factor. but theories say that i cannot design any circuit wit Q factor more than 10. I found some recent publications with Q factor as high as 3000. please help me sort out the issue

 

[LvW]

hi, I am trying to design an active inductor with a high quality factor. but theories say that i cannot design any circuit wit Q factor more than 10. I found some recent publications with Q factor as high as 3000. please help me sort out the issue

* At first - show your active inductor circuit
* Secondly - which theory says that the upper limit is Q=10 ? (It depends on the chosen circuit)

 

[tuza2000]

hi, I am trying to design an active inductor with a high quality factor. but theories say that i cannot design any circuit wit Q factor more than 10. I found some recent publications with Q factor as high as 3000. please help me sort out the issue

what technology?which layer? what's the layer material? all these will be matter.:wink:

 

[D.A.(Tony)Stewart]

Obviously frequency range, feedback gain and parasitic values will affect Q which is the impedance ratio of reactive to real that controls gain. and 3dB bandwidth for a 2nd order circuit.

 

[BradtheRad]

There is also the op amp's output resistance. If this is high then it will reduce Q.

This is in line with the usual observation that higher Q goes with small ohmic resistance. It produces more 'purity' of behavior from the inductor (or capacitor).

 

[D.A.(Tony)Stewart]

Although Zout is << 1 mOhm due to 100% feedback Values for R1 as low as 1 Ohm would work but only for low voltage as the real limiting case is the current limit of OpAmps, which can easily be boosted with cascaded buffers but linear efficiency power loss becomes the next limit...