LF412-N

www.ti.com

SNOSBH7E – APRIL 1999 – REVISED MARCH 2013

A feedback pole is created when the feedback around any amplifier is resistive. The parallel resistance and

capacitance from the input of the device (usually the inverting input) to AC ground set the frequency of the pole.

In many instances the frequency of this pole is much greater than the expected 3 dB frequency of the closed

loop gain and consequently there is negligible effect on stability margin. However, if the feedback pole is less

than approximately 6 times the expected 3 dB frequency a lead capacitor should be placed from the output to the

input of the op amp. The value of the added capacitor should be such that the RC time constant of this capacitor

and the resistance it parallels is greater than or equal to the original feedback pole time constant.

TYPICAL APPLICATION

Figure 32. Single Supply Sample and Hold

Copyright © 1999–2013, Texas Instruments Incorporated

Submit Documentation Feedback

11

Product Folder Links: LF412-N