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At 3:34 of the video he says high-speed op-amps suffer from the parasitic capacitance effect.

Why do we have parasitic capacitance on the minus leg, and not on the load?

What is special in high-speed op-amps that can cause that?

I'll be happy to have some op-amp model example to see this effect.

Video.

enter image description here

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    \$\begingroup\$ We do have parasitic capacitance on the load. The difference is that the impedance driving the load is low, so the parasitic capacitance doesn't have the same effect as it does on the extremely high impedance input node. \$\endgroup\$
    – John D
    Commented Feb 2 at 17:57
  • \$\begingroup\$ Parasitic capacitances are present on both inputs of the operational amplifier. This is an interesting article : allaboutcircuits.com/technical-articles/… \$\endgroup\$
    – Vincent
    Commented Feb 2 at 19:20
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    \$\begingroup\$ you have it everywhere; on the + terminal, but it's not part of the feedback loop going thru the output ; on the load, it is driven at lower impedance \$\endgroup\$
    – Pete W
    Commented Feb 2 at 22:00
  • \$\begingroup\$ Hello , Could you please give me an example to a High speed opamp who has this problem and low speed opamp who does not has this problem? \$\endgroup\$
    – Josh23
    Commented Feb 3 at 5:10
  • \$\begingroup\$ any op amp where the loop bandwidth ( = GBW / 2, in the video example) is higher than the frequency of the pole introduced into the feedback path \$\endgroup\$
    – Pete W
    Commented Feb 3 at 16:47

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A capacitor is two conductor plates sandwiched around an insulator. The inputs of high-input-impedance op amps generally FET gates, which can behave very much like one of the plates of a capacitor

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  • \$\begingroup\$ Hello , Could you please give me an example to a High speed opamp who has this problem and low speed opamp who does not has this problem? \$\endgroup\$
    – Josh23
    Commented Feb 3 at 5:10

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