| 摘要 |
An op amp includes a pair of buffer amplifiers interposed between the current switch and the output transistors in an output stage based on the Monticelli architecture. The buffer amps buffer the output transistors' gate capacitances, thereby allowing the output transistors to be nearly any desired size without adversely affecting the op amp's dynamic performance. This enables the op amp's compensation capacitors to set the amplifier's bandwidth, and allows the secondary pole to be at a higher frequency. The buffer amplifiers can also provide gain which effectively multiplies the transconductance of the output transistors and further extends out the secondary pole location. In addition, the buffer amplifiers can be used to provide voltage level translation between the current switch and output transistors, which can provide additional headroom for the op amp's gain stage.
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