Question

The requirements for a good current source is the one in which, (Take Output current – IO and Output resistance – rO )

(a) IO independent upon current gain  and should be low

(b) rO should be very high

(c) IO in the circuit should be low

(d) IO independent upon current gain  and rO should be very high

I had been asked this question in quiz.

Origin of the question is Operational Amplifier Internal Circuit in division Operational Amplifier of Linear Integrated Circuits

Answer 1

Right answer is (d) IO independent upon current gain  and rO should be very high

Here's the scoop: The need for high output resistance current source can be seen because the common mode gain of the differential amplifier can only be reduced by using high resistance current sources.