How to minimize noise of OTA in unity feedback?

I get the input referred noise, which is proportional to 1/gm

You got this because the output noise is divided by the DC gain of the OTA, which is not the case in real application.
Theorically you could reduce gm to reduce noise. However, the other specifictions which are related to gm may be deteriorated, like the DC gain of the OTA which is needed to be high in high linearity application.

In a word, noise cannot be considered seperately,otherwise the circuit may fail to meet other requirement.

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sharkies said:

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

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