PCB track width?

per_electric · 05:30 PM

Hi!

I'm in the middle of designing a PCB for an audio power amplifier. However I don't know how to estimate how wide the tracks have to be for the more high-current parts, like output, ground connections, power rails etc. Also, I'm not very familiar with calculating the maximum currents that can be expected in these lines.

Any input much appreciated!!

Thanks!
Per

peranders · 07:14 PM

For 10 A you'll need approx. 5 mm traces at 70 um and signal traces 0.5 mm.

PCB Trace Width Calculator
http://circuitcalculator.com/wordpre...dth-calculator

Trace width is very dependent if the trace is at the edge of the board, if the pcb is mounted horizontally or vertical etc.

Mooly · 27th October 2009, 07:24 PM

Remember also that when it comes to grounds you MUST consider what is actually going to be flowing in the conductors too. You HAVE to design so that all signal grounds are uncontaminated. Increasing the print size 10 fold will not eliminate this kind of issue.

As a classic example of that only today I was looking at an old Rotel amp and the 1 inch or so square copper print that connects the two smoothing caps together has a clearly visible ripple component across it of the order of several millivolts.

You must treat each conductor as a resistance... if it helps put nominal values in of say 1 ohm and ask yourself "would that cause a volt drop that would influence the signal ? " the answer must be NO

peranders · 27th October 2009, 07:34 PM

Ground is very critical in good analog pcb's so it can be a good idea to let us review your work, free of charge

per_electric · 27th October 2009, 07:58 PM

That would be very kind of you!!

So, as I understand it, the best thing you could do is separate all the signal grounds from all the other grounds, and then run two individual cabels to the star ground?

Steerpike · 27th October 2009, 11:37 PM

Tinning the track manually, with a good thickness of solder, can up its current rating significantly.

Speedskater · 28th October 2009, 12:12 AM

Tinning a solid wire continuously to the track helps even more.

h_a · 6th November 2009, 12:50 PM

Tin is by a factor of 10 a worse conductor than copper, any solder ontop of a trace maybe looks good but won't lower resistance much.

Anyway, with 70mum boards currents as high as 15A are not a big deal anyway.

Have fun, Hannes

wwenze · 6th November 2009, 01:00 PM

Would the tinning result is sonic changes like tinned copper vs untinned copper wires?

peranders · 6th November 2009, 01:29 PM

This is a typical question with two answers:

Yes

No

27th October 2009, 05:19 PM	#1
per_electric diyAudio Member Join Date: Jan 2008	PCB track width? Hi! I'm in the middle of designing a PCB for an audio power amplifier. However I don't know how to estimate how wide the tracks have to be for the more high-current parts, like output, ground connections, power rails etc. Also, I'm not very familiar with calculating the maximum currents that can be expected in these lines. Any input much appreciated!! Thanks! Per Last edited by per_electric; 27th October 2009 at 05:30 PM.

27th October 2009, 07:10 PM	#2
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	For 10 A you'll need approx. 5 mm traces at 70 um and signal traces 0.5 mm. PCB Trace Width Calculator http://circuitcalculator.com/wordpre...dth-calculator Trace width is very dependent if the trace is at the edge of the board, if the pcb is mounted horizontally or vertical etc. __________________ /Per-Anders (my first name) or P-A as my friends call me Tube Buffered Gainclone in work \|Thread Last edited by peranders; 27th October 2009 at 07:14 PM.

27th October 2009, 07:34 PM	#4
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	Ground is very critical in good analog pcb's so it can be a good idea to let us review your work, free of charge __________________ /Per-Anders (my first name) or P-A as my friends call me Tube Buffered Gainclone in work \|Thread

27th October 2009, 11:37 PM	#6
Steerpike diyAudio Member Join Date: Jan 2006 Location: Johannesburg, South Africa	Tinning the track manually, with a good thickness of solder, can up its current rating significantly. __________________ Steerpike's Toybox

28th October 2009, 12:12 AM	#7
Speedskater diyAudio Member Join Date: Sep 2002 Location: Lakewood, Ohio	Tinning a solid wire continuously to the track helps even more. __________________ Kevin


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

27th October 2009, 07:24 PM	#3
Mooly diyAudio Moderator Join Date: Sep 2007	Remember also that when it comes to grounds you MUST consider what is actually going to be flowing in the conductors too. You HAVE to design so that all signal grounds are uncontaminated. Increasing the print size 10 fold will not eliminate this kind of issue. As a classic example of that only today I was looking at an old Rotel amp and the 1 inch or so square copper print that connects the two smoothing caps together has a clearly visible ripple component across it of the order of several millivolts. You must treat each conductor as a resistance... if it helps put nominal values in of say 1 ohm and ask yourself "would that cause a volt drop that would influence the signal ? " the answer must be NO

27th October 2009, 07:58 PM	#5
per_electric diyAudio Member Join Date: Jan 2008	That would be very kind of you!! So, as I understand it, the best thing you could do is separate all the signal grounds from all the other grounds, and then run two individual cabels to the star ground?

6th November 2009, 12:50 PM	#8
h_a diyAudio Member Join Date: Sep 2006 Location: Graz, Austria	Tin is by a factor of 10 a worse conductor than copper, any solder ontop of a trace maybe looks good but won't lower resistance much. Anyway, with 70mum boards currents as high as 15A are not a big deal anyway. Have fun, Hannes

6th November 2009, 01:00 PM	#9
wwenze diyAudio Member Join Date: Mar 2008	Would the tinning result is sonic changes like tinned copper vs untinned copper wires?

6th November 2009, 01:29 PM	#10
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	This is a typical question with two answers: Yes No __________________ /Per-Anders (my first name) or P-A as my friends call me Tube Buffered Gainclone in work \|Thread

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
am i on the right track??	dawgbite	Subwoofers	9	26th April 2006 07:46 AM
SE 813 OPT..Am I On the right Track?	valveitude	Tubes / Valves	4	12th June 2005 02:33 PM
Table of Track Width vs Current?	richie00boy	Parts	2	29th November 2004 07:13 AM
PCB track spacing (HV)	keyne	Parts	3	1st November 2004 04:57 AM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read