Hi All, I certainly agree with some of the authors that the current carrying capability of a solderball can not be solely determined by considering the solderball as a seperate entity. The current capacity could mainly be influenced by the quality and the metallurgy of the Solderball/ soderballpad interface. My question would be whether the ball falls off before it melts? By the way, I have not come across any technical paper on this issue, although I have been looking for it for some time. If anybody has any reference that points out to measured data. PLease forward a copy to me , I would be very interested. Regards, Ozgur Misman Aubrey_Sparkman@xxxxxxxx@freelists.org on 02/05/2003 02:39:48 PM Please respond to Aubrey_Sparkman@xxxxxxxx Sent by: si-list-bounce@xxxxxxxxxxxxx To: weirsp@xxxxxxxxxx, mchan@xxxxxxxxxxx, BSchieck@xxxxxxxxxx, si-list@xxxxxxxxxxxxx cc: Subject: [SI-LIST] Re: Current capacity of a Solder Ball Steve, Let's assume that all your numbers are correct. I had the same conclusion several years ago at a previous company. We both missed the main point of Pat's email: You need to re-think what the limiting factor is. It's not immediately obvious. Aubrey Sparkman Signal Integrity Aubrey_Sparkman@xxxxxxxx (512) 723-3592 > -----Original Message----- > From: steve weir [mailto:weirsp@xxxxxxxxxx] > Sent: Wednesday, February 05, 2003 3:07 PM > To: mchan@xxxxxxxxxxx; BSchieck@xxxxxxxxxx; si-list@xxxxxxxxxxxxx > Subject: [SI-LIST] Re: Current capacity of a Solder Ball > > > > Moses, and Brian, that current number seems low by orders of > magnitude. First, the electrical resistance is way off. For the > resistivity value shown which seems about right at 8X Cu, and > a rectangular > section 0.2mm X 0.2mm X 0.6mm yields about 0.002 ohms. > > Similarly, the thermal resistance value of 41,000 C/W for a > metallic object > 24 thousandths thick cannot be right. Take a small glob of > solder the size > of a BGA ball on the bench and connect it to a 10V supply and > a 100 ohm > resistor. There is no way, that blob will get warm, much > less melt. It > will take multiple amperes to melt the foil leading to or > away from the > ball, and the foil will fail long before the ball. > > Regards, > > > Steve. > > At 11:32 AM 2/5/2003 -0800, Moses Chan wrote: > > >Hi Brian, > > > >I asked the same question to the list a few months back and got the > >following answer, below: > > > >Solder Ball (63Sn/37Pb) 0.0006 m > >Ambient Temp. 34 Deg. C > >Melting Temp. 189 Deg. C > >Thermal Conductivity 50 W/m-C > >Electrical Resistivity 0.000000145 ohm-m > >Thermal Resistance 41026.51161 C/W > >DC Electrical Resistance 0.297442209 ohm > >Total Resistance 0.297442209 ohm > >Power to Melt 0.003778045 W > >Current to Melt 0.112702164 Amps > > > > > >Moses Chan > >Vitesse Semiconductor > >Camarillo, California > > > >At 11:13 AM 2/5/03 -0800, Brian Schieck wrote: > > > > >Does any one know what the current carrying capacity of a > solder ball is? > > >How is the capacity determined? > > >Is the capacity derated to account for temperature and voids? > > > > > > > > >for a 60 mil solder ball. > > > > > >Brian Schieck > > >NVidia Corporation > > >2701 San Tomas Expressway MS B22-221 > > >Santa Clara, California 95050 > > >Direct Phone # (408) 486-2697 > > >Corp Phone # (408) 486-2000 x62697 > > >Local Fax # (408) 486-8078 > > >Corp Fax # (408) 486-2200 > > > > > >Email bschieck@xxxxxxxxxx > > >------------------------------------------------------------------ > > >To unsubscribe from si-list: > > >si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the > Subject field > > > > > >or to administer your membership from a web page, go to: > > >//www.freelists.org/webpage/si-list > > > > > >For help: > > >si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field > > > > > >List archives are viewable at: > > > //www.freelists.org/archives/si-list > > >or at our remote archives: > > > http://groups.yahoo.com/group/si-list/messages > > >Old (prior to June 6, 2001) list archives are viewable at: > > > http://www.qsl.net/wb6tpu > > > > > > >------------------------------------------------------------------ > >To unsubscribe from si-list: > >si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field > > > >or to administer your membership from a web page, go to: > >//www.freelists.org/webpage/si-list > > > >For help: > >si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field > > > >List archives are viewable at: > > //www.freelists.org/archives/si-list > >or at our remote archives: > > http://groups.yahoo.com/group/si-list/messages > >Old (prior to June 6, 2001) list archives are viewable at: > > http://www.qsl.net/wb6tpu > > > > ------------------------------------------------------------------ > To unsubscribe from si-list: > si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field > > or to administer your membership from a web page, go to: > //www.freelists.org/webpage/si-list > > For help: > si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field > > List archives are viewable at: > //www.freelists.org/archives/si-list > or at our remote archives: > http://groups.yahoo.com/group/si-list/messages > Old (prior to June 6, 2001) list archives are viewable at: > http://www.qsl.net/wb6tpu > > > ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu