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-   -   LM3886 library for Eagle 5 (http://www.diyaudio.com/forums/chip-amps/175320-lm3886-library-eagle-5-a.html)

Redshift187 13th October 2010 11:48 PM

LM3886 library for Eagle 5
 
1 Attachment(s)
Here is an Eagle 5 library for the LM3886 with two versions. The second one has the N/C pins removed so you can use the extra space to route traces.

ratza 14th October 2010 08:00 AM

Routing can be made over the n.c. pins anyway, since they are not connected to anything.

Redshift187 14th October 2010 01:40 PM

True, but it's better not to have unnecessary holes in the middle of traces or small antennae attached to them :)

ratza 15th October 2010 06:22 AM

You're absolutely right. In analogue electronics any pin is an input pin :D

nma550n 12th January 2012 09:56 PM

Hi Redshift I'm looking at the distance between the pins in Eagle and am not sure if they are ok.
The data sheet (Oct 2003) has the distance between the pins of 1.7mm. Your file has the gap at 1.79mm. I'm not sure how much that matters.
Can anyone confirm?

madtecchy 13th January 2012 06:15 AM

Hi

0.09mm is the small diffrence Hardley worth worrying about at that pin spacing.

Regards Ian

pacificblue 14th January 2012 08:27 AM

10 x 0,09 = 0,9 mm. It will make a difference, even if it is not as bad as in the lmopamp libraries you can download from the Eagle homepage.

The holes are too small. The pins are 0,97 0,12 mm by 0,41 0,05 mm. The diagonal will be 1,053 0,13 mm, which means the drill must be 1,1 mm for most pins to fit. You will even need 1,2 mm for those with positive tolerances.

For the complete package it will be handy to have the N/C pins in the symbol as well, so you can actually use them for routing. They will rather improve mechanical stability and a wee bit heatsinking, than act as antennae.

It would also be nice, if symbol and package had a name and a value. Add >NAME in the tNames layer and >VALUE in the tValues layer.

In my version I set the center of pin6 at the origin. That way you don't need to correct the position depending on Imperial or metric layouts.

madtecchy 14th January 2012 09:28 AM

Pacificblue..

I suggest you take an lm3886 and measure the pins. the measurements in the data sheet are nominal. Also you may have noticed the setting of the pins is never that perfect as they get moved in the handleing packaging process..Also if you would like to post your PERFECT lm3886 footprint i will etch a board with the OP's I.C footprint and yours then post piccys of the result. As for the unused pins if you are worried about them acting as antennaes that much remove them from the I.C altogether .

Regards Ian

pacificblue 14th January 2012 07:36 PM

I don't see the point of measuring pins, etching boards for comparison, up- and downloading files and pics, when it is so easy to correct the coordinates in the Eagle file according to the 'nominal' datasheet dimensions.

As for the unused pins, the worries about the antennae did not come from me. My suggestion is, if you draw a version with and one without the N/C pins, the version with them should offer the possibility to include them in the PCB routing, too. Otherwise you either have to route around them or mess around with unnecessary DRC error messages.


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