Electronics Forum: basic (Page 81 of 142)

Help needed to solder poorly designed SMT LED's

Electronics Forum | Wed Sep 25 05:08:33 EDT 2002 | msimkin

Gregg, We had a similar problem with our 0603 leds. They were being placed bang on, however, during the reflow, they twisted, fell sideways etc. We played with our profile, played with the paste volume & land pattern design, and only had a small impr

Lattice Orca heatsink to PCB

Electronics Forum | Thu Dec 19 20:40:08 EST 2002 | jonfox

One common practice, depending on what is on the other side of the PCB and how much heat you need to draw away from the part, is to manufacture a pseudo-heatsink into the board itself. It looks like a large tinned pad but has a dense array of vias f

Lattice Orca heatsink to PCB

Electronics Forum | Thu Dec 19 20:45:47 EST 2002 | jonfox

One common practice, depending on what is on the other side of the PCB and how much heat you need to draw away from the part, is to manufacture a pseudo-heatsink into the board itself. It looks like a large tinned pad but has a dense array of vias f

Flux Selection

Electronics Forum | Mon Dec 30 01:52:13 EST 2002 | MA/NY DDave

Hi I see DaveF already gave some good stuff. You should read or at least review some of the texts he listed or some others in the same subject areas of SPC (Statistical Process Control) or DOE (Design of Experiments). I won't list the other publish

Foam Fluxer - Porous Cylinder

Electronics Forum | Fri Dec 27 14:21:11 EST 2002 | MA/NY DDave

Hi DaveF, Thanks a Good to Great approach. I would still recommend getting another one, just in case. I am never too sure about how anyone follows procedures and maybe the start up just won't go well for some reason and you don't want to piddle a

RS-232 Help?

Electronics Forum | Fri Dec 27 16:24:01 EST 2002 | Matt Foster

As a project I am trying to design a circuit that transmits data to the 9 pin serial port (RS232) of a standard PC. As a basic start I am trying to make a circuit with 4 ptm switches, when I press switch 1 I would like to display "switch 1" or some

BGA voids

Electronics Forum | Thu Jan 16 04:02:18 EST 2003 | johnw

The IPC 610 actally conflict's with 7095 which give's a better indication of what's acceptable. I believe that IPC are reviewing both. Motorola did a bunch of work before basically showing that void's aren't that bad up to a certain size, I think pro

RMA vs No clean

Electronics Forum | Thu Jan 16 15:16:52 EST 2003 | Mike Konrad

You are comparing apples to oranges. No-clean fluxes, because they are designed not to be cleaned off after reflow, contain very low solids. Normally, no-cleans have a solids content of 2% - 5%. Your basic RMA has a solids content of 15% to 30% (s

Plated through via's in pads.

Electronics Forum | Wed Feb 05 13:08:20 EST 2003 | joeherz

You're correct that a thicker solder deposit will make bridging on fine pitch devices a bigger risk. Another alternative could be to slightly over-print the pads (onto the soldermask) ala pin-in-paste process. Basically adding enough solder to fill

Recommended TG material for CCBGA , CBGA and PBGA's

Electronics Forum | Mon Mar 03 13:22:20 EST 2003 | MA/NY DDave

Hi I see David F already gave a good answer. The basic advantage, if you can afford it, is a more stable PCB during the soldering process. Higher Tg enables this. Also some materials serve to match CTEs (coefficient of thermal expansion) a bit bett


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