Electronics Forum | Fri Mar 03 10:07:15 EST 2000 | Wolfgang Busko
Hi Jacqueline, - what a name in this technical world - I just tried the calculator and for example choose the CQFP and then selected other and an input mask appeared where you have to fill in the required data from the components datasheet. I have to
Electronics Forum | Wed Mar 08 10:52:27 EST 2000 | Wolfgang Busko
Hi Jacqueline, for the "manufacturing allowance" IPC says FAB.TOL. is the board manufacturing tolerance and PLACE ACRCY is the pick and place accuracy. For 0,8 mm pitch they give for both values 0,1 mm. Solder joint design goal data comes from empir
Electronics Forum | Wed Mar 01 17:13:15 EST 2000 | Dave F
Sorin: Formulas for calculating heat dissipation of traces don�t seem to provide practical results. But there are some wonderful tables and graphs that will meet you needs. You may need to do some finagling when calculating vias and through holes,
Electronics Forum | Tue Feb 29 13:18:16 EST 2000 | Steve Schrader
We have what appears to be a recurring problem. On immersion gold boards only, we are having solderability problems. After reflow, selected parts can be popped right off the board. There is then a dark haze left on the pad. The paste on the compon
Electronics Forum | Wed Mar 01 17:03:56 EST 2000 | Dave F
Steve: Someone is trying to trick you. He/she is trying to be very smart, but he/she didn�t anticipate this "dark haze" coating problem. I suspect that this person is someone you speak with every day in your plant. They may be the one that came-u
Electronics Forum | Thu Mar 02 21:24:27 EST 2000 | Dave F
Glen: As I mention in an earlier response in this thread, I think someone at Steve's plant (or may be in his packaging spec for the fabs) is doing something to leave a residue, but I'm also thinking solder mask ... ENIG can be applied before or aft
Electronics Forum | Tue Feb 29 10:14:02 EST 2000 | Robert Hartmann
My company is just getting into the flip chip packaging arena. We are putting in a prototype/small volume wire bond PBGA line. We have some questions with regard to choosing solder balls and cleaning of flux. 1) Is there a formula for the shrink
Electronics Forum | Tue Feb 29 21:53:46 EST 2000 | Kelvin Chow
Dear Robert, On PBGA assembly, BGA sphere shrinkage number depends to the following factors, a. BGA Sphere size (before reflow) b. Solder mask opening diameter As far as I know, no formular has been established yet. Most of my friends just collect
Electronics Forum | Mon Feb 28 20:17:02 EST 2000 | Eldon Sanders
I need to side mount a standard HC-49/U crystal on a board using double sided foam tape. I am looking for a source for pre-cut foam tape. In prototype runs I have used 3M #4950 foam tape cut to size one at a time. But for production I want it pre-
Electronics Forum | Mon Feb 28 19:36:39 EST 2000 | Tony
I work for a contract manufacture of PCB's, we are also in the BGA rework business. We see all kinds of different size boards, as well as different types of BGA's and micro BGA's. We selected the Conceptronics Freedom 2000 over the Air Vac and SRT. T
