I want to build a simple amplifier with TI's TPA3116D2, which is "filterless" Class-D amplifier. This device can be run with a traditional LC filter at the output, or, if the speaker wires are short, simply a ferrite bead with a 1nF capacitor.
I'd like to test with a traditional LC filter. The example values in the datasheet are 10uH and 680nF.
I don't happen to have any 10uH coils, but I have plenty of 22uH ones. What happens if I use a larger inductance and smaller capacitance?
According to my calculations, the suggested filter has a 61KHz cutoff frequency and 3.8 ohms impedance. A filter made with 22uH and 330nF will have a 59KHz frequency but the impedance will be 8.16 ohms
What does this mean in this case? Will it affect the performance of the device?
Answer
I don't happen to have any 10uH coils, but I have plenty of 22uH ones
Wire two in parallel to get 11 uH - this is near enough 10 uH so I don't see a big issue given that inductors are usually toleranced at greater than +/- 10% (yes I know there are exceptions)
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