The surface of a trace covered with soldermask will sit higher than the
exposed pads of a two-terminal component. This may cause the component with
a trace routed between the pads to sit tilted on the pads like a see-saw
pivoting over the trace. The effect is worse for smaller packages and for
components with terminations that are level with the bottom of the component
(typical for 0603, 0402 resistors). The ultimate result may be dewetted
joints and tombstoning.
I would route between the pads only as a last resort. Some companies demand
that all PCB symbols are coded with a route keepout between the pads of
small two-terminal devices.
Med vennlig hilsen. Best Regards.
________________________________
Haldor Husby, Senior Development Engineer
Data Respons Norge AS
Kongsberg Næringspark
N-3601 Kongsberg, Norway
Tel: +47 32 39 94 18
Cell: +47 480 48 368
[log in to unmask]
On Wed, 29 Mar 2006 16:37:48 -0800, Jaurique, Brad <[log in to unmask]> wrote:
>I am debate with some people in regards to routing through pads
>of components (i.e diodes, caps, Resistors) I was always taught
>not to do this but I can't remember from whom. Especially with
>the smaller and smaller these parts are getting. But I am seeing
>this being done today more often at my work by other designers.
>
>I also see necking down to route in between connectors,
>and IC's.
>
>Please let me know what others are doing and why.
>
>I am currently training 2 new designers to my company and I want
>to make sure I am guiding them in the right direction.
>
> I never got the luxury of being guided at work but have taken many
>classes
>over the years from people such as Mary Sugden, Gary Ferrari,
>Wayne Pulliam and many more. This instructors have instilled in my
>a great set of design philosophies that have made me a successful
>designer and I want to make sure I do the same with whomever I get
>the luxury of training.
>
>Thank you all for your help in advance.
>
>
>
>
>
>
>Brad Jaurique C.I.D.
>Senior PCB Designer
>Pelco
>(559)292-1981 ext. 2347
>[log in to unmask]
>Tell me and I forget; Show me and I remember; Involve me and I
>understand.
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