Frequency responce of op amp

The gain of op amp decreases with increase in frequency. What is the reason?

Hi,

1. Since the parameters like current gain of transistors reduce with increasing frequency, the gain of the individual stages start falling at high frequencies.

2. Stray capacitors also reduce the load resistances of the stages thus bringing down the gain at high frequencies.

3. Apart from these, the main reason for the reduction of the op-amp gain is due to the fact that the gain is allowed to roll off to below unity at high frequencies by design. This is so, because most of the opamps are used in feedback applications and for stability of the feedback circuit it is required to bring down the high open loop gain below unity following a planned roll off scheme before the stray componenets starts introducing undesirable phase shifts. This will ensure that the amplifier works stably under various feedback conditions.

Regards,
Laktronics