[PCB_FORUM] Re: 0402, 0603 round pads

The beveled and/or D-shape pads just allow for more "warm-n-fuzzy" room.
A manufacturer that is churning out millions of assemblies takes the
time to adjust wave solder and or reflow belt speeds and temperatures.
When you are only having low volumes assembled, the rounded or beveled
pads enhance the manufacturability. 

Also, a beveled pad allows 45 degree trace entry and a D-shape pad
allows any angle entry so you don't have to worry about acute angles
creating acid traps during fabrication.

I am not advocating these types of pads except for use when your
assembly vendor is not spending the time to work out the best yields.
All PCB layout designs are different and the small end assembly vendors
are not going to spend as much effort in determining the ideal (highest
yield) solder adherence approach and that is usually included in your
price.

Just my humble opinion.

 

Jim S. Wages / SR. PCB Layout Designer:  

Cary, NC - H: 919-466-1596 Cell: 919-484-2963

 

-----Original Message-----
From: icu-pcb-forum-bounce@xxxxxxxxxxxxx
[mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx] On Behalf Of
sjchar3@xxxxxxxxxxxx
Sent: Friday, January 05, 2007 12:01 PM
To: icu-pcb-forum@xxxxxxxxxxxxx
Subject: [PCB_FORUM] Re: 0402, 0603 round pads

 

Is this the snow and round pad discussion group? I think the round pads
could allow more routing room.  

 

 
-----Original Message-----
From: allegrolist@xxxxxxxxxxxx
To: icu-pcb-forum@xxxxxxxxxxxxx
Sent: Fri, 5 Jan 2007 9:52 AM
Subject: [PCB_FORUM] Re: 0402, 0603 round pads

Hi Gary,

 

No, but I spent quite a bit of time there years ago.  I'm in Harvard,
MA.

 

Regards,

 

Austin

-----Original Message-----
From: icu-pcb-forum-bounce@xxxxxxxxxxxxx
[mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx]On Behalf Of Macindoe, Gary
Sent: Friday, January 05, 2007 11:46 AM
To: icu-pcb-forum@xxxxxxxxxxxxx
Subject: [PCB_FORUM] Re: 0402, 0603 round pads

Hmm. I thought you were in Boulder Austin?  Guess not!

 

 

Gary E. MacIndoe

PCB Design Engineer

Longmont, Colorado

 

amd.com

gary.macindoe@xxxxxxx


  _____  


From: icu-pcb-forum-bounce@xxxxxxxxxxxxx
[mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx] On Behalf Of Austin Franklin
Sent: Friday, January 05, 2007 9:38 AM
To: icu-pcb-forum@xxxxxxxxxxxxx
Subject: [PCB_FORUM] Re: 0402, 0603 round pads

 

Hi Gary,

 

I keep hearing and seeing you guys are getting pummeled.  We have had NO
SNOW!!!  And, it's supposed to be 63F tomorrow!

 

Regards,

 

Austin

 

-----Original Message-----
From: icu-pcb-forum-bounce@xxxxxxxxxxxxx
[mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx]On Behalf Of Macindoe, Gary
Sent: Friday, January 05, 2007 11:17 AM
To: icu-pcb-forum@xxxxxxxxxxxxx
Subject: [PCB_FORUM] Re: 0402, 0603 round pads

Hey Austin,

 

Are you tired of the snow yet?!?  I shoveled out this morning before
coming in to work!  It's a good workout!

 

I can see the benefit of using them on the bottom side, but I'm seeing
them on top also.

 

Regards,

Gary

 

 

Gary E. MacIndoe

PCB Design Engineer

Longmont, Colorado

 

amd.com

gary.macindoe@xxxxxxx


  _____  


From: icu-pcb-forum-bounce@xxxxxxxxxxxxx
[mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx] On Behalf Of Austin Franklin
Sent: Thursday, January 04, 2007 7:53 PM
To: icu-pcb-forum@xxxxxxxxxxxxx
Subject: [PCB_FORUM] Re: 0402, 0603 round pads

 

Hi Gary,

 

I use round pads for my 0402s on the opposite side of 1mm BGAs.  That
way I can keep the decoupling caps and termination resistors right
there.  Works fine, haven't had any yield problem.

 

Regards,

 

Austin

-----Original Message-----
From: icu-pcb-forum-bounce@xxxxxxxxxxxxx
[mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx]On Behalf Of Macindoe, Gary
Sent: Thursday, January 04, 2007 6:05 PM
To: icu-pcb-forum@xxxxxxxxxxxxx
Subject: [PCB_FORUM] 0402, 0603 round pads

Hey guys,

 

Man has it been quiet (or am I not receiving forum e-mails?).

 

So, I've been looking at some designs from a couple of other groups
within the company.

Both of them have their 0402 and 0603 foot prints with round pads (0402
= rd25).

 

Is anyone out there also using round pads for 0402s and 0603s, and why?

 

They have oval pads for their 0805s and 1206s also.

 

I still have square or rectangular for all of the above.  Could it have
something to do

with lead free?

 

Thanks and Happy New Year!

 

Gary

 

 

Gary E. MacIndoe

PCB Design Engineer

Longmont, Colorado

 

amd.com

gary.macindoe@xxxxxxx

 

  _____  

 
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