Operational Amplifier Circuits

CHAPTER

Frequency

Response

2.1

Open

Loop

Behavior,

Compensation

The circuits discussed in the previous chapter all depended on the assumption

that the open loop gain A remains very large (ideally infinite) under all operat-

ing conditions. In practice, this cannot be true for all frequencies. For stable

operation with the feedback configurations used, the high gain must be pre-

served for low frequencies, including dc (zero frequency).

However, for stable operation under all conditions, the gain must be

made to fall or "roll off at high frequencies. This will occur in any case due to

stray capacitance, but additional capacitance is also used