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My first completed PCB design, High End LM317 regulator! Ready to do the first PCB!

post #1 of 33
2/17/11 at 4:12pm
Thread Starter 

Hi!

 

I have been playing with ExpressPCB. It seems to be quite easy to use but it is pretty basic still. It is very addicting to design PCBs with it.

 

I have been working on TPA6120 amplifier but I need to first try to etch something simpler with wider traces.

 

I have not yet tried to do the toner transfer but I think this LM317 reg is very good candidate for first try.

 

Check it out:

 

LM317regulatorExpressPCB.png

 

ExpressPCB layout file:

http://dl.dropbox.com/u/7337908/LM317powersupply.pcb

 

I decided to set the output voltage with two 12V zener diodes. I found that info from here: http://tech.juaneda.com/en/articles/lm317.html

 

Any tips are appreciated! I have magazine paper , laser printer, press and peel blue and iron , and single sided copper pcb and other basic pcb manufacturing items. I will be using ferric chloride as etchant.

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post #2 of 33
2/17/11 at 5:47pm

It looks like you have most of your traces on the top side with

all of your through hole components. This will make for very

poor physical mounting for these components. In a commercial

board with plated through holes it might not be so bad, but on

a do it yourself board it will rip the traces off.

 

The traces look a bit out of alignment in places but over all

not a bad first try.

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post #3 of 33
2/17/11 at 6:27pm
Thread Starter 
Quote:
Originally Posted by Avro_Arrow View Post

It looks like you have most of your traces on the top side with

all of your through hole components. This will make for very

poor physical mounting for these components. In a commercial

board with plated through holes it might not be so bad, but on

a do it yourself board it will rip the traces off.

 

The traces look a bit out of alignment in places but over all

not a bad first try.


Thanks, that was valuable information! I didn't think about that at all!

 

I therefore removed the smd components and tried to make the traces a little bit shorter. And marked them to the bottom side.

 

lm317regulatorver2.png

 

 

ExpressPCB file:

http://dl.dropbox.com/u/7337908/LM317powersupply1.pcb

 

Now I realized that the bottom copper won't cool the regulator at all, or would it if the mounting screw and nut transferred the heat to the bottom side?

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post #4 of 33
2/17/11 at 6:53pm

Is that big red trace really going to be there?  It is connecting a lot of stuff together that it shouldn't.

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post #5 of 33
2/17/11 at 7:15pm
Thread Starter 
Quote:
Originally Posted by cobaltmute View Post

Is that big red trace really going to be there?  It is connecting a lot of stuff together that it shouldn't.



Oh, you're right, when I print it I must remove that trace. It is supposed to illustrate where I should put a jumper wire.

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post #6 of 33
2/17/11 at 7:24pm

With a little bit of work, you should be able to do the board with no jumpers and on a single layer.

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post #7 of 33
2/17/11 at 8:23pm

Here is my version...

 

317.png

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post #8 of 33
2/18/11 at 4:33am

Here are some links to help you with your etching...

 

Easy Toner Transfer

 

Photo Etching Method

 

Rate my Etching Job

 

Good luck with your project!

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post #9 of 33
2/18/11 at 4:57am

Nice layout Avro_Arrow.

 

A little tip to improve it even further: try to tie the ground side of the components going to the adj. pin directly at the output gnd pad, even if it means a jumper, so that charging current of the output caps don't interfere with regulation.

 

edit: ALW on diyaudio made it clear with that picture:

 

adj[1]. reg wiring.gif

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post #10 of 33
2/18/11 at 5:10am

Thanks 00940 for the compliment.

 

I know what you mean about the ground.

If I re-draw this I will see if I can sneak it down the middle

between the filter caps.

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post #11 of 33
2/18/11 at 5:41am

How is this one?

 

317a.png

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post #12 of 33
2/18/11 at 6:50am

 

Quote:
Originally Posted by Spacehead View Post


Oh, you're right, when I print it I must remove that trace. It is supposed to illustrate where I should put a jumper wire.


No. Just make that trace around LED or between resistor's legs. There is no need for double sided pcb or jumper.

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post #13 of 33
2/18/11 at 4:58pm
Thread Starter 
Quote:
Originally Posted by akgfan View Post

 


No. Just make that trace around LED or between resistor's legs. There is no need for double sided pcb or jumper.



I tried:

lm317regulator2.png

 

http://dl.dropbox.com/u/7337908/LM317powersupply2.pcb

 

I don't dare to begin the pcb making process yet because I am unsure about my layout still.

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post #14 of 33
2/18/11 at 5:25pm

I would scrap the idea of using the board as any kind of heat sink.

Your traces are way to long and convoluted. Play around with the

layout to make the traces shorter and more direct.

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post #15 of 33
2/18/11 at 8:14pm

Maybe this will give you an idea.  My schematic is not exactly the same, but it should be close enough.

 

lm317-single layer.png

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