Calculate the output offset voltage the circuit fig

EXAMPLE 14.6
		Figure 14.24

Solution

Eq. (14.16):	R1�Rf 2 k��1 50 k�

R
V�o� I�IBRC�1 ��R��1

while the output voltage due to only I�IB, denoted by V�o, is

Figure 14.25				Redrawn circuit of Fig. 14.25.
626	Chapter 14			Redrawn circuit of Fig. 14.25.

Vo(offset due to I�IBand I�IB) � I�IBRC�1 ��R�� I�1 IBR1�R�

R1, using RC � R1 in Eq. (14.17) we can write

Vo(offset) � I�IB(R1� Rf) � I�IBRf

EXAMPLE 14.7

Eq. (14.18):	Vo � IIO Rf � (100 nA)(150 k�) � 15 mV

TOTAL OFFSET DUE TO VIO AND IIO

be either positive or negative.

Calculate the total offset voltage for the circuit of Fig. 14.27 for an op-amp with spec-ified values of input offset voltage, VIO � 4 mV and input offset current IIO �150 nA.	EXAMPLE 14.8

14.5		627