"Chapter 1 - The Op Amp's Place in the World" - HTL Wien 10

This simplifies the gain calculation:
E 0 E in
R2 R1 2
e n1 R 2
2
R1 where e n = the total noise over the bandwidth of interest.
10.5.5 Noninverting Op Amp Circuit Noise
Op Amp Noise Theory and Applications
Op Amp Noise
(10–19)
Taking the simplified equivalent op amp circuit from Paragraph 10.5.2 as the base, the
noise equivalent of a noninverting op amp circuit is shown in Figure 10–11:
Ein
R1
_
+
en
_
Noiseless
Op Amp
Figure 10–11. Noninverting Equivalent Op Amp Circuit Noise Model
The gain of this circuit is:
E0 Ein1 R 2
2
e
R
n1
1
R
2
2
R1 +
R2
E0
(10–20)
10-17