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I'm generating a clean sine wave signal of about 4V of amplitude from the IC XR2206 and I need to amplify the signal to about 10V of amplitude, I'm using the following amplifier:

enter image description here

Still, on the oscilloscope, the output signal is completely damaged, it is basically a triangle wave with about 1V of amplitude.

I have simulated a 600 ohm resistance as it is supposed to be the output impedance of the XR2206.

Any solutions?

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  • \$\begingroup\$ What frequency are you generating from the 2206? What supply voltages are you using? What op-amp are you using? \$\endgroup\$
    – Andy aka
    May 14, 2014 at 19:13

1 Answer 1

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A triangle wave TYPICALLY means that you are running into the slew rate limitation of your amplifier. What's the frequency of the sine wave and what's the part number of the amplifier?

If that is the case, the solution is an amplifier with higher slew rate. The max dv/dt of a sine wave F=A*sin(wt) is found by differentiating F: A*w*cos(wt) and finding the maximum, which is obviously A*w. So the slew rate of your amplifier should comfortably exceed that value.

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  • \$\begingroup\$ bold Its an ua741, the max dv/dt is almost 3E6 and i used an lm833 with a slew rate of 7E6 with no luck \$\endgroup\$
    – JsMartinez
    May 14, 2014 at 15:56
  • \$\begingroup\$ On a different subject because of the inverting configuration and the 600 ohm output impedance, you will only have a gain of 2.5, not 4. If you use a non-inverting configuration you won't have that problem. \$\endgroup\$
    – John D
    May 14, 2014 at 16:19
  • \$\begingroup\$ So your frequency is 3MHz? The gain-bandwidth of the LM833 is 16MHz, and your noise gain is 3.5, giving you a 3dB bandwidth of around 4.5MHz. So given your original gain of 2.5 and the fact that you're a couple of dB down you won't get near your goal of 4V out. Is your amplitude still 1V? Is it still triangular? \$\endgroup\$
    – John D
    May 14, 2014 at 16:23
  • \$\begingroup\$ I used another IC, the lf351 that has much bigger slew rate and everything works fine \$\endgroup\$
    – JsMartinez
    May 14, 2014 at 22:58

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