Improving a PAM8403 amp.

[Redfoxuk]

Im making a small custom amp circuit, it needs to be low power. So the PAM8403 Seems ideal and is nice and cheep.
(Any other suggestions in same power range would be good)

Im working towards building the circuitboard my self and have a schematic for this version.

But I have also spotted this one that seems to have more compponents.

So im assuming there ways i can improve on the design for cleaner output ect. Any one got some schematics for this IC?

 

[FauxFrench]

https://www.diodes.com/assets/Datasheets/PAM8403.pdf
Page 1 and 9.

 

[Redfoxuk]

Sweet so that helps me remove any possible noise.

Doesnt help with why these two boards have different setups.
Why does the second have two extra electrolytic capacitors when the other had none?

First board has 10 extra components and second has 11 (two being the electrolytics)

My schematic has.

Im still learning and quite noob, hoping to get the best sound possible from this lil IC =)

 

[tomchr]

They're not electrolytic caps. They're tantalum caps. Both types are polarized, but one uses wet chemistry while the other is essentially metal deposited on a 'sponge'.

Tom

 

[Redfoxuk]

ah right, what would be best? The first example seems to only be using ceramics.

 

[tomchr]

You do need some bulk capacitance on the board, so I'd probably go with the version that has the tantalum caps unless the version with the ceramic caps has a pair of huge ceramics on the back of the board. Without measurements, I really can't tell, though.

Tom

 

[Redfoxuk]

Im trying to make a schematic, im not just taking the board so if people have schematics pleaaaase share. I have no idea where to add the extra caps.

 

[tomchr]

I suggest reading the data sheet for the part if you haven't already. You usually find a good schematic there. Then just follow the guidelines for how to use the chip in the Application Section of the data sheet.

Tom

 

[Redfoxuk]

before I go ahead with my project fully. Can anyone suggest a better amp IC with similar specs? cheep would be good lol (I dont need any of the mute functions ect, ins and outs is enough)

 

[PRR]

https://www.diodes.com/diodes-part-files/KR/PAM8403/User Guides and EV Boards/PAM8403 User Guide.pdf

 

[Redfoxuk]

Iv read the data sheet propperly now and viewd various sites/threads and board schematics to try find the best method to wire this.

I have added a 1000uf decoupling capacitor to the 5v input
Im already ready to add ferrite beads to the audio inputs if needed.

One schematic shows me that I need more components for my stereo jack.
Is this correct? Or is there a more elegant solution? Less parts would be useful as Im working in a very small space.

I will post my schematic soon if anyone is happy to double check my work.
Also if there is any info on spacing and layout of the board people have that would be great. (Say if one part needs to be close to an output to reduce noise ect?)

 

[nigelwright7557]

Reminds me of 1980 when my electronics class all built LM386 amplifiers as a task.
Pretty much everyone's oscillated and blew up !
The decoupling, layout and power supply all need to be just right.

 

[Redfoxuk]

This is what im trying to find info about haha, I just keep getting data sheets. This is a accidental double post btw.. There is an identical post thats got more traction.

 

[tomchr]

Also if there is any info on spacing and layout of the board people have that would be great. (Say if one part needs to be close to an output to reduce noise ect?)

Follow the recommendations in the data sheet. It's always a good idea to keep nodes with switching noise as short or small as possible.

Tom