Go Back   Home > Forums > Amplifiers > Chip Amps

Chip Amps Amplifiers based on integrated circuits

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 Search this Thread
Old 4th July 2005, 02:31 AM   #1
diyAudio Member
 
Join Date: Dec 2004
Location: Brisbane
Question LM1875 PCB Layout

Hi Guys,

I'm currently building a 5 channel chipamp and have finally come up with a PCB design (took me a while to learn how to use Eagle).

I've attached the schematic and board for your perusal. Could you guys please go through my PCB layout and give me any hints and tips on ways to improve it.

Keep in mind that I'm planning on eventually having 5 of these PCB's side by side so the design is intended to be as small as possible long the width.

I've based my schematic on carlosfm's snubber design and Nationals datasheet schematic and will be using his design also for the power supply.

Amy I missing anything as I have seen in a few schematics for chipamps that they have around 2.2k ohm resistor inline with the positive input to the chip. What is this for and do I need it?

Thanks.
Attached Images
File Type: gif lm1875 schematic.gif (9.4 KB, 1417 views)
  Reply With Quote
Old 4th July 2005, 02:33 AM   #2
diyAudio Member
 
Join Date: Dec 2004
Location: Brisbane
Smile Board layout

Here's the board layout:
Attached Images
File Type: gif lm1875 board.gif (15.6 KB, 1439 views)
  Reply With Quote
Old 4th July 2005, 04:48 AM   #3
homer09 is offline homer09  Canada
diyAudio Member
 
homer09's Avatar
 
Join Date: Jan 2004
Location: Montreal
Default Re: LM1875 PCB Layout

Quote:
Originally posted by mangrovejack


Amy I missing anything as I have seen in a few schematics for chipamps that they have around 2.2k ohm resistor inline with the positive input to the chip. What is this for and do I need it?

Thanks.
this is a "safety" resistor used in series with positive input. it is used to reduce dc offset, or protect against some dc incoming mostly on power up/down. with a cap at the input i think you could get away without that resistor.
__________________
Most people wouldn't know good music if it came up and bit them in the ***. - Frank Zappa
  Reply With Quote
Old 4th July 2005, 05:43 AM   #4
diyAudio Member
 
metal's Avatar
 
Join Date: Jan 2004
Hello

Can you please upload eagle files you are working on + LM1875 Library.

Thanks
  Reply With Quote
Old 4th July 2005, 07:31 AM   #5
Banned
 
Join Date: Jan 2005
Output2 should be going to ground and Output1 remains on the opa output.
  Reply With Quote
Old 4th July 2005, 07:34 AM   #6
diyAudio Member
 
Join Date: Dec 2004
Location: Brisbane
Quote:
Originally posted by Tekko
Output2 should be going to ground and Output1 remains on the opa output.
I'm not sure what you mean by that?

Maybe I should have explained why I have two "outputs". It was because one wire pcb terminal wouldn't be stable enough (only one leg to solder), so I thought I'd just use a double one ant leave one output empty.

<Edit>Ah, I understand what you mean now. I'm getting the output ground from the star ground at the caps, and not on the PCB to reduce the possibility of hum.</edit>
  Reply With Quote
Old 4th July 2005, 07:37 AM   #7
diyAudio Member
 
Join Date: Dec 2004
Location: Brisbane
Sorry Tekko, I edited my post as you were sending yours.
  Reply With Quote
Old 4th July 2005, 07:38 AM   #8
Banned
 
Join Date: Jan 2005
Oops I deleted my last post.
  Reply With Quote
Old 5th July 2005, 02:04 AM   #9
diyAudio Member
 
Join Date: Dec 2004
Location: Brisbane
So no-one can see any problems with this layout? That's great then, as I can start making the PCB and testing it out.

I'll report back the results when I'm done.
  Reply With Quote
Old 5th July 2005, 06:06 PM   #10
diyAudio Member
 
metal's Avatar
 
Join Date: Jan 2004
Hello

Can you please upload schematic, PCB, and LM1875 library
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Eagle vs. Sprint-Layout for PCB design/layout hollowman Parts 11 12th January 2014 09:01 PM
Please check my LM1875 PCB layout Dominique Chip Amps 27 15th January 2009 04:36 PM
super small lm1875 layout available? nerd of nerds Chip Amps 0 14th April 2006 05:34 AM
Need LM1875 PCB layout !! thomgun_lc Chip Amps 9 10th May 2005 11:35 AM


New To Site? Need Help?

All times are GMT. The time now is 01:28 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2