Part Number: LM48310SDBD_NOPB
Hey guys, I've been developing my own pcb that is a circuit comprising of the Teensy 3.2, Pjrc Prop shield, and Sparkfun 5v/1A boost converter (to power the Audio amplifier - LM48310). I'm using the Teensy audio library to send audio to a single 4 Ohm speaker. The problem I'm having is with my custom pcb, when i go over 0.7 gain with a saw wave at 160hz, the audio amplifier (or potentially the capacitors connected to it) shorts out and completely breaks. The circuit will only function again after i disconnect the broken amplifier , and until then the entire circuit is unresponsive. Everything works perfectly underneath a gain of 0.8, I have also tested full volume on the premade boards and it works without issue. When the amp died after going up to 0.8 gain, I actually saw the board spark out of the corner of my eye , but I'm not sure exactly where the spark was, other that it was in the area of the audio amplifier. The only thing I can think of is that my capacitors are placed incorrectly, and running high power through them is causing a short to happen through the air. I'm attaching screenshots of my pcb design and schematic, if anyone can comment that would be an amazing help! The board is 2 layers, with a ground pour on the bottom. The audio amplifier has a heat dissipating ground pour on the top layer too.
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I will take a look at this and will answer as soon as possible.
Best regards,Luis Fernando Rodríguez S.
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In reply to Luis Fernando Rodriguez S.:
Thank you Luis,
I've been advised by the creator of the Pjrc prop shield that I should make my 4.7uf capacitor (c20) closer to the chip with small traces connecting it. Here's my updated design. Any other insight would be appreciated. :)
In reply to Ben Cooper1:
Sorry for the delay on my response and thank you for your update.
In addition, are C11, C12, C15 & C16 ceramic capacitors? We strongly recommend to avoid capacitors with polarity.
The rest of the LM48310 schematic portion looks fine.
Do you have any update on this?
Please, feel free to post your observations on this. We will be glad to assist you.
Hi Luis, sorry for the lack of reply.
My capacitors are ceramic and without polarity.
Ive ordered a new revison of my board with a better layout, which should arrive in the next few days.
Ill test it and update you on the situation.
Thanks again for your help!
Thank you for your response. We will be waiting for your update.
In the meantime, I will close this E2E thread. But please feel free to post your observations on this thread or in a new one in order to continue the support.
I found that the problem was the main capacitor, it was of low quality and only rated for 10v, which wasn't enough.
Replaced with a higher quality capacitor and it works correctly now.
I'm sure the layout change helped too.
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