I have seen a schematic where they used MAX3221, RS232 Driver and Receiver. There they have used LC filter of inductor value 0.68uH and capacitor value of 680pF, but in datasheet they have not mentioned about frequency. Can anyone explain how they selected this value?
I am designing an LC filter with a cut-off frequency of 20 kHz for the Class-D amplifier. The filter schematic is shown in Fig.1 top right. I understand how to choose the LC values for the critically damped case for the pure resistive load as shown in Fig. 2.
The problem is I want to drive...