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diegot 23rd October 2006 11:10 PM

TDA2050 Oscillating
 
2 Attachment(s)
I'm prototyping a board for the TDA2050, but it has a buzz at the output and if I touch the potentiometer at a certain position I can hear a local radio playing at the speaker.
For now I'm using 100n ceramic paralleled with the 220u caps. When done, I will use polyester ones. The resistor and the cap paralelled with the 22k resistor(feedback) are not present and I don't have the 220p cap in the input to ground.
I'm using the components values suggested in the datasheet and the PCB it's based on the layout presented in the datasheet, too.

There is something wrong with my layout?

diegot 23rd October 2006 11:11 PM

Schematic
 
2 Attachment(s)
Here is the schematic that I'm using.

diegot 23rd October 2006 11:14 PM

2 Attachment(s)
The amplifier assembled

pinkmouse 24th October 2006 12:12 AM

Stick a 0.01uf across the input + and -.

sivan_and 24th October 2006 05:10 AM

diegot !!!
It is NORMAL..that BUZZZing sound when u touch the inputs...I don't thing u need to worry abt that....unless u always keep your fingers on the input pins :-) :)

sivan_and 24th October 2006 05:11 AM

diegot !!!
It is NORMAL..that BUZZZing sound when u touch the inputs...I don't thing u need to worry abt that....unless u always keep your fingers on the input pins :)

diegot 24th October 2006 03:08 PM

sivan_and
it's not about the buzz when touching the input, but it is always present.
I put a 150p cap before the 1k res going to ground, and the oscilations apears to went away. For now I a have a few problems that I believe it's relationed with the power supply, because some falls caused by a shot-circuit, my fault.

I still want to know what you thing about my layout.

sivan_and 25th October 2006 06:49 AM

I didn't find any problem with the layout....Check the resistor values in the gain setting...might've used wrong values..resulting in very high gain and oscillations !!

sivan_and 25th October 2006 07:06 AM

I didn't find any problem with the layout....Check the resistor values in the gain setting...might've used wrong values..resulting in very high gain and oscillations !!


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