Not to mention adding copper on boards has its own impact.
Changing pads size and trace length will have in impact on some assemblies.

As usual there are unintended consequences for any change.


On Tue, Jun 26, 2018 at 11:14 AM Stadem, Richard D <[log in to unmask]>
wrote:

> From the equations I have in my files for solder joint reliability, all of
> the dimensions have some effect on modulus of elasticity of the resultant
> solder joint, and the height is the most critical factor. A radical change
> in the overall solder geometry WILL have a huge effect on the reliability.
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Nutting, Phil
> Sent: Tuesday, June 26, 2018 8:58 AM
> To: [log in to unmask]
> Subject: Re: [TN] Passive component downsizing
>
> We were notified many "common" 0603 MLCCs were going to 52 week lead
> times.  The world is going to smaller packaging.  Ok, so how do I make 20
> kilowatts with 0402 parts?  We work in brute force, 1,200 volts at 100
> amps, and still use thru hole parts because they can handle the power.  I
> can see it now, we will use fifty 0201 resistors to get the power level we
> need.  Geesh!
>
> It is going to be interesting how we build in a world of smaller parts.
>
> I know, you can't buy a '57 Chevy new anymore.  But imagine if you could
> Cool!
>
> Phil
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Nigel Burtt
> Sent: Tuesday, June 26, 2018 9:48 AM
> To: [log in to unmask]
> Subject: Re: [TN] Passive component downsizing
>
> Of course, hence "...suitably limited implementation..." in my post.
>
> I'm thinking of assembly problems: printing, SPI, placement, reflow, AOI
> etc -  even if one could come up with a suitable mixed footprint stencil
> aperture, would the resulting solder joint meet IPC-A-610 visual inspection
> acceptability conditions for example.
>
> Then there is the in-service-reliability aspect of the solder joints
>