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