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Hello everyone!

I’m trying to solve a problem that asks for the total noise spectral density observed at the output of an operational amplifier. I have some questions regarding the calculation and would appreciate some help.

Regarding the bias current noise of the operational amplifier, should I consider both resistors in the circuit (R1 and R2) when calculating the input current error? Or should I treat each resistor separately

I’m using the following formula to calculate the total noise spectral density:SV(f)total=√(en)2+(iner1×R1)2+(iner2×R2)2+4.1×√R11k+4.1×√R21kSV(f)total=(en)2+(iner1×R1)2+(iner2×R2)2+4.1×R11k+4.1×R21k

But I'm not sure if im doing correctly the analysis. The problem provides the values for the input voltage noise (En=7.9nV/sqrt(Hz)) and input current noise (in=0.5fV/sqrt(Hz)), that 4.1 is the spectral density for 1kΩ in 1 hz, and also mentions that the BW=100Hz.

Could anyone confirm if my approach is correct, or if there’s anything I should adjust?

Thanks in advance for your help!