Hi,
Page 13 of the LM2578 datasheet shows a diode needing to be used so as to protect the internal NPN drive transistor. However, the MC33063 is pretty much the same device, and yet there is no such warning about needing such a diode.
Do you think the MC33063 also needs this diode?
The LM2578 datasheet says the protection diode is needed because the NPN base is clamped near ground when its off…..but surely so too would the MC33063’s when the NPN is off?