Hello!
Im building a LM4780 stereo amplifier as my schoolwork. Im using one chip for two channels with 36V rails. The problem is that it produces too much heat. I could only try it for like 5 seconds before it was too hot for my fingers. Of course i used heatsink.
I used signal generator for testing.. I have double checked everything and there should not be any problems. I used the schematic found in the datasheet.
Heres some pictures:
Picture 1
Picture 2
Picture 3
Thank you!
Im building a LM4780 stereo amplifier as my schoolwork. Im using one chip for two channels with 36V rails. The problem is that it produces too much heat. I could only try it for like 5 seconds before it was too hot for my fingers. Of course i used heatsink.
I used signal generator for testing.. I have double checked everything and there should not be any problems. I used the schematic found in the datasheet.
Heres some pictures:
Picture 1
Picture 2
Picture 3
Thank you!
Use a kitchen towel to wipe that flux off the solder with some acetone. I'm pretty sure I see some solder droplets crossing rails or bridgeing them close enough to cause problems with capacitive coupling. like the 6th pin from the left on the botton row in the second picture also the 3rd from left in that row, looks bent suspiciously close to the ground plane.
To me it looks like Nordic has a point. I don't like the looks of those solderings either. Some heavy solder droppings scattered all around, and i'm not sure if my eyes are fooling me, but to me it looks like a dry solder at picture 2, second soldering from beneath at the far right side.
Resolder, and clean up, that may do it.
Also a good magnifying glass could be handy.
Good luck
Ebbe
Resolder, and clean up, that may do it.
Also a good magnifying glass could be handy.
Good luck
Ebbe
There is no solder droppings really.. its just some dirt sticked in to pcb. Some of the joints arent so good because the pads are too small. There should not be any flux left on pcb.
Anyway i will try to solder it once more. Thanks for the tips..
I used electronic microscope to solder the chip in the first time
Heres a screenshot..
Anyway i will try to solder it once more. Thanks for the tips..
I used electronic microscope to solder the chip in the first time
Heres a screenshot..
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