Bias of an inverting amplifier

RHF330

18/22

Doc ID 15576 Rev 3

7

Bias of an inverting amplifier

A resistance is necessary to achieve good input biasing, such as resistance R shown in

Figure 32.

The value of this resistance is calculated from the negative and positive input bias current.

The aim is to compensate for the offset bias current, which can affect the input offset voltage

resistance R is:

Figure 32.

Compensation of the input bias current

R

R

in

R

fb

×

R

in

R

+

fb

------------------------

=

R

Load

Output

R

fb

R

in

I

ib

-

I

ib

+

V

V

CC

-

+

_

AM00839