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I am currently learning to design an op-amp, and understand that using compensation capacitors help to maintain stability of the op-amp.

Currently, my compensation capacitor has a value around 10 pf. I would like to know what will happen if I increase this value to 30 pf, how is the gain bandwidth product affected?

Thank you.

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  • \$\begingroup\$ What op-amp are you using? \$\endgroup\$
    – Andy aka
    Commented Oct 26, 2016 at 14:26
  • \$\begingroup\$ @Andy aka LM301 \$\endgroup\$
    – samheihey
    Commented Oct 26, 2016 at 14:27
  • \$\begingroup\$ See figure 18 in the data sheet. \$\endgroup\$
    – Andy aka
    Commented Oct 26, 2016 at 14:58

1 Answer 1

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The whole point of the compensation cap is to make a LPF that dominates all the higher frequency Gain-Bandwidth tradeoffs such that the net gain vs f is dominated by the C added to internal current signal. The result is a controlled open loop LPF with a breakpoint of like 10 Hz and gain of like 1e6 for a GBW product of 1e7.

Increasing the Compensation cap x3 reduces the GBW product /3 so that closed loop gain-bandwidth is also affected but step response overshoot may be improved slightly if the compensation was not critically adjusted for critical dampening. ( ie not as dominant at unity gain as the net attenuation from all the internal stages cascaded near 1MHz)

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