sharkies
Member level 5
Let's say I have an opamp... actually is an OTA to be more exact
anyways..
I have a certain output noise, which is proportional to gm,
I get the input referred noise, which is proportional to 1/gm
Therefore, I can lower input referred noise by increasing gm, or burning more power.
What I don't understand is that very often OTA's are configured to have unity gain when used with feedback. In this case, output referred noise is equivalent to input referred noise. Since output noise is proportional to gm, we must lower gm to reduce the overall noise, which is the exact opposite of what I explained above. Is this right? I will be using my OTA in unity feedback, and I'm not sure how to minimize my noise because of this conflicting direction
anyways..
I have a certain output noise, which is proportional to gm,
I get the input referred noise, which is proportional to 1/gm
Therefore, I can lower input referred noise by increasing gm, or burning more power.
What I don't understand is that very often OTA's are configured to have unity gain when used with feedback. In this case, output referred noise is equivalent to input referred noise. Since output noise is proportional to gm, we must lower gm to reduce the overall noise, which is the exact opposite of what I explained above. Is this right? I will be using my OTA in unity feedback, and I'm not sure how to minimize my noise because of this conflicting direction