OPAMP input disturbed by noise

[hardings]

Hi,

I am designing a circuit, which noise is very serious, I put the noisy input to one input of the OPAMP,
and connect bandgap voltage to the other input, then the noise will increase the bandgap volgate.
Also I do some circuit to eliminate this effect, but my boss said it is too complex, anyone has some
simple ways to design this OPAMP?

Thanks

 

[tia_design]

I think your you should design a low noise op amp.

 

[hardings]

That is not my question,

My question is , an OPAMP with two input, one of the input signal is very noisy, and the noise voltage will distorb the value at the other input (bandgap voltage), How can I design the OPAMP to avoid disturbing?

 

[Shano]

maybe you could use a buffer stage to pre-filter the noisy input or putting a capacitor on the bandgap output to filter the coupled noise

 

[yibinhsieh]

Usually I will filter the noise source by a low pass filter and then input to the op-amp. So it will not disturb the bandgap voltage.

Yibin.