I want to amplify a signal from a DDS (AD9833) in order to feed an inductive load (27µH, 3 ohms) at 100kHz, amplitude around 3V.
When I use the OPA564 from Texas, everything works well. But this component is not available. So I tried to use the AD8655 but here is what I get :
As you can see, the current is good, but the voltage signal is a bit distorted a the max values, when the current is inversed. I guess it is linked to the back emf.
The 10µF capacitor is here to avoid the DC. Changing this capacitor doesn't change the distorsion. Symetric supply of the opamp and placing the µF capacitor between the DDS and the opamp doesn't change anything. When I increase the frequency, the signal is better. When I decrease it, the signal is worst.
Any idea of the reason of this phenomenon? Any idea how to solve it? Any idea radically different to feed my coil with these properties and without distortion?
Thank you very much!