Electronics Forum | Thu Jul 12 20:20:31 EDT 2007 | seankim10
I�m having problem with PCB with 16mil thickness due to warpage. the board convex up in the middle after 1st reflow. It seams the warpage is caused by CTE mismatch between PCB and multiple TSOP's, which are covering ~80% of the bottom side board area
Electronics Forum | Mon Sep 14 09:25:49 EDT 1998 | Dave F
0.050" -> 50 mil -> 50 pitch | 0.80 mm -> 0.032" -> 32 mil -> 32 pitch | 0.64 mm -> 0.025" -> 25 mil -> 25 pitch | 0.50 mm -> 0.020" -> 20 mil -> 20 pitch | 0.40 mm -> 0.016" -> 16 mil -> 16 pitch | 0.20 mm -> 0.012" -> 12 mil -> 12 pitch | Dave F Y
Electronics Forum | Wed Oct 17 10:37:13 EDT 2001 | davef
Help us understand your situation better: ARE THE QFP BOWED? If so, * Where are the QFP bowed? * Is the QFP body bowed or is it just the leads? * How much are the QFP bowed? * Are all QFP the same part number, from the same supplier, date code
Electronics Forum | Mon Feb 25 21:09:48 EST 2002 | davef
You are correct about a TCE [CTE] mismatch issues in ceramic packages. The coefficient of thermal expansion [ppm/�C] of major ceramic package elements are: * Silicon - 3 * Standard 92% alumina ceramic � 6.5 * FR4 board � 18-20 Several points are: *
Electronics Forum | Mon Sep 27 04:08:25 EDT 1999 | Earl Moon
| | | I am in the process of picking a new resistor network for one of our new board. Since we are new to SMT i would like to get some opinions on networks. Currently we use one molded gullwing type network on our boards with no problems. Other than
Electronics Forum | Mon Aug 28 12:41:35 EDT 2000 | JAX
MoonMan, I'll take a crack at the list. Feel free to answer the ones I don't! 1. Solderability is a parameter which indicates how well a component can be soldered. As far as Solder Termination Coatings go, here are some up�s and down�s of a few. Ha
Electronics Forum | Thu Jan 21 19:38:24 EST 1999 | dean
| Hello, | | I will be evaluating and qualifying two equipment types. The first is a fountain soldering device. I need practical advice on all the stuff you guys and gals know about as good, bad, ugly, best applications, setup, limitations, and all
Electronics Forum | Thu Jan 21 20:22:02 EST 1999 | Earl Moon
| | Hello, | | | | I will be evaluating and qualifying two equipment types. The first is a fountain soldering device. I need practical advice on all the stuff you guys and gals know about as good, bad, ugly, best applications, setup, limitations, an
Electronics Forum | Fri May 28 16:30:39 EDT 1999 | JohnW
| Yes l know this problem keeps cropping up on the forum but l've missed some of the follow-ups. | | Our problem is that the lifting only occurs on 3% of production so actually detecting an improvement is difficult. We're actually having to inspect
Electronics Forum | Thu Mar 30 21:46:56 EST 2000 | Dave F
Reg: This is copy / paste from draft version of IPC 7095 ( issued May 1999 ) ... 7.3 Assembly accept/reject criteria 7.3.1 Voids in solder joint a. Sources of Voids There can be voids in solder balls, or at the solder joints to the BGA, or at the so
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