Amplifier Question

Thread Starter

Tom88

Joined Oct 14, 2011
4
I got a question about amplifiers and noise. Does a inverting amplifier add more noise than a non inverting amplifier? My rails are +5V and -5V. The +5V has about 1mV or noise and the -5V has 2mv of noise.
 

#12

Joined Nov 30, 2010
18,210
True. An op-amp, or any other well designed amp, will reject power supply ripple and noise by virtue of the configuration of the transistors.

For really nit-picking noise calculations, the input and feedback resistors are usually the major noise source.
 

crutschow

Joined Mar 14, 2008
25,103
The intrinsic op amp input noise gain is amplified by the non-inverting gain or 1 + the inverting gain. Thus for a gain of 1 the inverting amp will have twice the noise gain for the op amp intrinsic input noise as the NI amp.
Edit: This is for the op amp input noise (in V/√Hz as given in the data sheet).
 
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