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Verify My PCB?

Rawr

Jul 11, 2009
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Jul 11, 2009
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PCB & Related Images: http://imgur.com/a/DyB07

The problem is that it doesn't work, period. It's a very simple board, so it can't be too hard to narrow down the problem. I've highlighted what I believe to be the trouble area.

In Image 2, it says to connect SGND to PGND.
In Image 1, the trace with the blue/yellow pattern is what SGND was before I merged it to PGND via the top 47uF capacitor.
Image 3 is the schematic that the PCB is built off of.

Note: Input's GND trace was added to the PCB manually, and connects to SGND.
 

OLIVE2222

Oct 2, 2011
690
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Oct 2, 2011
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690
Looks OK to me. Do you have connected the stand by pin? The IC pin's are staggered do you align them for mounting purpose ? Do you mount a correct heatsink?
 

Rawr

Jul 11, 2009
4
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Jul 11, 2009
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Yes, I aligned the pins for testing purposes.
As you can see, pin 7 (Stand-by) is connected to the positive side of the upper 47uF capacitor.
& I'm not sure what the "correct" heatsink would be, but there is a heatsink on the IC.. What qualifies as correct?
 

OLIVE2222

Oct 2, 2011
690
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Oct 2, 2011
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690
As it the pin is floating, the cap act just as a filter. You must connect the standby pin to gnd via a resisitor (see the STA540 datasheet).
The metal part on the componant is not a heatsink but a metal tab provided to attach a heatsink. Heatsink size will depend on many thinks (max power, ambiant t°, convection...) However you can have an idea by looking on the following:

http://www.ponoko.com/make-and-sell...r-kit-sta540?source_node=ponoko_united_states

http://targetearth.dyndns.org/gallery/showImage?image_id=P1010386.JPG&pathtype_id=22
 

davenn

Moderator
Sep 5, 2009
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As it the pin is floating, the cap act just as a filter. You must connect the standby pin to gnd via a resisitor (see the STA540 datasheet).

yes and reduce the cap value to the 10uF as shown in the cct ciag of the datasheet

see what happens :)

Dave
 

Rawr

Jul 11, 2009
4
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Jul 11, 2009
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Thanks guys. I replaced the cap with 10uF.. not sure why I was using 40uF.
But the solution came with the 10k resistor from ST-BY to VCC. After doing this, I finally got sound. :D I tried ST-BY to GND but it didn't work.

Now all I need to resolve is the popping/crunch every time the bass kicks.
 
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