Go Back   Home > Forums > >

Chip Amps Amplifiers based on integrated circuits

my first try at a LM3886 layout, any comments/suggestions?
my first try at a LM3886 layout, any comments/suggestions?
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
Reply
 
Thread Tools
Old 18th January 2005, 04:05 PM   #1
BrianGT is offline BrianGT  United States
diyAudio Moderator Emeritus
 
BrianGT's Avatar
 
Join Date: Jan 2002
Location: near Atlanta, GA
Send a message via AIM to BrianGT
Default my first try at a LM3886 layout, any comments/suggestions?

Here is my first try at an LM3886 layout. I have been sitting on this design for about 10 months now, and decided to put the last touchs on it last night. Let me know what you think.

btw: I am still backlogged in mails, and will try to catch up soon.

An externally hosted image should be here but it no longer works. Please upload images instead of linking to them to prevent this.


--
Brian
  Reply With Quote
Old 18th January 2005, 04:25 PM   #2
UrSv is offline UrSv  Sweden
diyAudio Member
 
UrSv's Avatar
 
Join Date: Jan 2002
Location: Sweden
Looks very good indeed. Can't wait to get myself a few of those.
__________________
UrSv
Those who say it can't be done should not stop those who are doing it.
  Reply With Quote
Old 18th January 2005, 04:49 PM   #3
BrianGT is offline BrianGT  United States
diyAudio Moderator Emeritus
 
BrianGT's Avatar
 
Join Date: Jan 2002
Location: near Atlanta, GA
Send a message via AIM to BrianGT
Thanks,

With regards to the layout, has anyone tried adding the mute capacitor to the layout? Is this a recommended addition? The datasheet seems to like 100uF for this. I was thinking about possibly adding the cap to the layout, based on a suggestion I received.

Also, would it make sense to add a jumper for allowing the mute functionality to be switched on and off?

--
Brian
  Reply With Quote
Old 18th January 2005, 05:17 PM   #4
r!sc! is offline r!sc!  Serbia
Account Disabled
 
Join Date: Jun 2003
Location: Serbia
Very nice

Boban
  Reply With Quote
Old 18th January 2005, 05:26 PM   #5
BrianGT is offline BrianGT  United States
diyAudio Moderator Emeritus
 
BrianGT's Avatar
 
Join Date: Jan 2002
Location: near Atlanta, GA
Send a message via AIM to BrianGT
Here is a version with the Cm cap added:
An externally hosted image should be here but it no longer works. Please upload images instead of linking to them to prevent this.


Datasheet says:
"Mute capacitance set up to create a large time constant for turn-on and turn-off muting."

The value in the datasheet is 100uF, and this will be an optional component, as is the zobel network components.

For using the larger BG capacitors, the cap can be omitted, or stuffed on the bottom of the pcb.

--
Brian
  Reply With Quote
Old 18th January 2005, 05:58 PM   #6
peranders is offline peranders  Sweden
Electrons are yellow and more is better!
diyAudio Member
 
peranders's Avatar
 
Join Date: Apr 2002
Location: Göteborg, Sweden
my first try at a LM3886 layout, any comments/suggestions?
You shouldn't snubberize you design? Why don't you add 100 nF/63V polyester/ceramic + 1 ohms so Carlos will get happy? At least 100 nF would be good I think.

The grounding looks good! :up.
__________________
/Per-Anders (my first name) or P-A as my friends call me
  Reply With Quote
Old 18th January 2005, 06:01 PM   #7
BrianGT is offline BrianGT  United States
diyAudio Moderator Emeritus
 
BrianGT's Avatar
 
Join Date: Jan 2002
Location: near Atlanta, GA
Send a message via AIM to BrianGT
Quote:
Originally posted by peranders
You shouldn't snubberize you design? Why don't you add 100 nF/63V polyester/ceramic + 1 ohms so Carlos will get happy? At least 100 nF would be good I think.

The grounding looks good! :up.
Sounds like an idea for the snubber stuff. I will work up a new power supply board, and see how it looks. I can add a few pads for the localized decoupling caps on the pcb.

--
Brian
  Reply With Quote
Old 18th January 2005, 07:11 PM   #8
BrianGT is offline BrianGT  United States
diyAudio Moderator Emeritus
 
BrianGT's Avatar
 
Join Date: Jan 2002
Location: near Atlanta, GA
Send a message via AIM to BrianGT
Quote:
Originally posted by peranders
You shouldn't snubberize you design? Why don't you add 100 nF/63V polyester/ceramic + 1 ohms so Carlos will get happy? At least 100 nF would be good I think.

The grounding looks good! :up.
How does this look for the "snubberized" rectifier board?
An externally hosted image should be here but it no longer works. Please upload images instead of linking to them to prevent this.


A few extra pads can be added to the main amp board for the extra decoupling caps.

--
Brian
  Reply With Quote
Old 18th January 2005, 07:15 PM   #9
peranders is offline peranders  Sweden
Electrons are yellow and more is better!
diyAudio Member
 
peranders's Avatar
 
Join Date: Apr 2002
Location: Göteborg, Sweden
my first try at a LM3886 layout, any comments/suggestions?
I think you should have this snubber close to the supply pins, not far away.

I think also that the speaker trace is a bit thinn. Remember that you have at least 11 A worst case. I recommend a 150 mils trace.

I would aslo recommend that you make a decent schematic. It must be pretty easy with your cad program.

Check also the insulation distance between the screwholes and the supply planes. It's too tight according to my taste. Have you take the screw head into account?

Why don't you move all designators so you can see those even when the parts are there? It much easier to troubleshoot!
Picture here as an example. I have even drawn lines, check T10!
http://home5.swipnet.se/~w-50674/hif...r0_topview.jpg

You power supply has a but thin traces, 150 mil or even more! Route the trace to the capacitor and the route from, not add this short "inductance". It is proabaly nothing but check Joseph_K's measurements about the influence of unnecessary inductance.
__________________
/Per-Anders (my first name) or P-A as my friends call me
  Reply With Quote
Old 18th January 2005, 08:01 PM   #10
carlosfm is offline carlosfm  Portugal
Banned
 
Join Date: Mar 2003
Location: Lisbon, Portugal
?iginally posted by peranders [/i]
You shouldn't snubberize you design? Why don't you add 100 nF/63V polyester/ceramic + 1 ohms so Carlos will get happy? At least 100 nF would be good I think.[/QUOTE]

Why would I be happy?
Actually, it's time to talk about $$$$, if this is to be included in a commercial PCB.

Are you recommending the snubber now?
  Reply With Quote

Reply


my first try at a LM3886 layout, any comments/suggestions?Hide this!Advertise here!
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


New To Site? Need Help?

All times are GMT. The time now is 02:27 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.
Copyright ©1999-2021 diyAudio
Wiki