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Slew rate problems at high frequencies

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saurabh17g

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The slew rate of the opamp we consider Vp or Vp-p rite i.e.
SR = 2*pi*fmax*Vp-output
or
2*pi*fmax*Vp-p-output ?

my sine wave is of form Vout = 2.5(1+sin(wt)).
and by this, Slew Rate required for my circuit = 15.7V/us which is less than the one specified in datasheet(17V/us). So, would the slewrate limitation problem occur?
 

keith1200rs

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Maximum slope of a sine wave is 2*pi*Vp so that is the figure to use, not peak to peak. Bear in mind the values in the data sheet are "typical" and quoted at a specified load so it would be risky to assume you can run so close to the datasheet value. I would like a reasonable margin between what is theoretically required and what the opamp produces.

Keith.
 

saurabh17g

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Thanks keith1200rs,
But will it change for offsetted sinewave? This is because, when we consider a square wave it is 0 to 5V. In the diagrams and explanation of slew rate, as shown in https://www.amplifier.cd/Tutorial/Slew_Rate/SlewRate.htm of the square wave , they have not shown negative cycle of square wave. So, i substituted my sinewave(since its offsetted/unidirectional) for that square wave and then found that slew rate should be theoretically 2*pi*fmax*Vp-poutput
 

keith1200rs

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I cannot see why offset should make any difference until you are near the limits of the output voltage where the slew rate reduces.

While simulations are not a perfect, a quick simulation with the OP37 confirms that.



Keith.
 

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