Propeller Head Plaza

Posted by Scott Frankland (M) on July 23, 2003 at 01:16:05

In Reply to: Re: Isn't Slew Rate a bit like THD? posted by john curl on July 22, 2003 at 23:11:53:

"To get significant TIM, you have to have a dominant pole within a feedback loop that is significantly lower than the working bandwidth of the system. Therefore, if you have an open loop bandwidth (dominant pole) of 1MHz, then you won't have any TIM distortion below 1MHz. However, you can have plenty of harmonic distortion that is frequency sensitive, due to non-linear cap effects."

You are right. OTOH, if the non-linear C effects are built into the Spice model, the distortion could also be due to phase modulation (PIMD). Someone will have to take a closer look at that model. If, however, the model does not include non-linear C effects, then we have to assume that there is some form of slew-rate limiting (AIMD).