Offset Voltage Calculation for Inverting Amplifier

This section details the calculation of the output offset voltage contribution stemming from the input offset current ($I_{IO}$) in an inverting operational amplifier (op-amp) configuration.

Relevant Formula

The output offset voltage ($V_{out, OS}$) caused by the input offset current ($I_{IO}$) is often calculated using the feedback resistor ($R_F$). A common approximation, particularly when focusing on $I_{IO}$'s impact, is:

$V_{out, OS} \approx I_{IO} \times R_F$

Given Values

• Input Offset Current ($I_{IO}$): $100 \;\text{nA}$ which is $100 \times 10^{-9} \;\text{A}$
• Feedback Resistor ($R_F$): $150 \;\text{k}\Omega$ which is $150 \times 10^3 \;\Omega$

Calculation Steps

Substitute the given values into the formula:

$V_{out, OS} = (100 \times 10^{-9} \;\text{A}) \times (150 \times 10^3 \;\Omega)$

Perform the multiplication:

$V_{out, OS} = 15000 \times 10^{-6} \;\text{V}$

Convert the result to millivolts:

$V_{out, OS} = 15 \times 10^{-3} \;\text{V}$

Final Offset Voltage

The calculated offset voltage is 15 mV.