Hi
I am currently working on my first audio design project and it's for a portable haptic device. The output load is an 8ohm voice coil actuator. The TPA2025D1 chip seems perfect for the project as it's class-D (less heat dissipation), very small and doesn't require much circuitry around it (circuit area is a deciding factor). What I want to do is do some experiments and play around with input/output filters. I have been using this schematic of the TPA2025D1 Evaluation Module as reference:
In my design I leave the power stage essentially unchanged but I would like to experiment with the values of C1, C2, C7, C8 (skip C6) and would also like to see the effect of an LC filter at the output.
The fact that the TPA2025D1 is a BGA chip has caused me some problems as I'm not sure how to handle the prototyping. Originally, I had the BGA chip mounted on an adapter from Proto-Advantage to allow for testing on a bread board. Those tests proved unsuccessful as I could never get a clear output signal. An example in the image below:
According to a staff member at the Texas Instruments Live Chat, it is not a good idea to use a bread board for audio amplifiers as it's very susceptible to noise. Although I'm not convinced that the results above are due to noise susceptibility, I still think it's best that I change my approach. So what I want to do now is make a few PCB's that I can use for further experiments, with the TPA2025D1 and power stage components assembled and the filter components unassembled. Here is a sketch of what I have in mind:
Since the 0.5mm pitch BGA package calls for microvias and multiple layers, the manufacturing cost is pretty high. So I want to be sure if the design above will work and if I'm safe to assume that all I have to do is add input and output filters to play around with the frequency response.
I'd really appreciate it if someone with experience would review my design and let me know if I'm overseeing something and/or if my approach makes any sense.
