Question

What is the voltage transfer function of op-amp in s-domain.

(a) S×A/(s+ωo)

(b) A/(s+ωo)

(c) (A×ωo)/(s+ωo)

(d) None of the mentioned

The question was posed to me during an internship interview.

The query is from Open-Loop Voltage Gain as a Function of Frequency topic in section Practical Limitations of Op Amp Circuits of Linear Integrated Circuits

Answer 1

Accurate choice is (c) (A×ωo)/(s+ωo)

Here's an easy explanation: For the voltage transfer function in s-domain is expressed as AOL(f) = A/[1+ j(f/fo)] =A/[1+j(ω/ωo)]= A×ωo/(jω/jωo) = A×ωo / (s+ωo).