phase Margin and low power

[m_kuty]

Hi

I have op-amp circuit and there is changing in phase margin with different power supply.

My question is
1. why is it changing?
2. is this related to the power (or current) consumption. and How?
3. is there any reference to go back for it?

 

[crutschow]

What op amp?

 

[m_kuty]

inverting circuit.

I would to know why the phase Margin changing if I change power supply?

thank you:clap:

 

[KlausST]

Hi,

What op amp?

This is the question to the answer. You need to know it's inside circuit, not it's external circuit.
I assume with changing power supply there will be changing inside currents causing the phase or gain to change (open loop).

Klaus

 

[m_kuty]

Thank you for reply

I Know the structure of the op-amp but I need to know what is the relationship between phase margin and he power (or current) consumption.

 

[CataM]

What part number has the OP Amp ?

 

[m_kuty]

What part number has the OP Amp ?

I don't Know what are you meaning by part number?
The op-amp is a two stage CMOS amplifier and I am using cadence for simulation phase margin.

 

[t4_v]

Power supply changes means bias conditions changes and hence you have different AC characteristic. There is no formula for this. The same is why AC characteristic changes across corners. From the same reasons. Different bias conditions.

 

[dick_freebird]

If bias current has a supply dependence then so will
other attributes such as bandwidth and stability. A
solid quiet bias generator and distribution is key to
PSRR and consistency of frequency response.