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sachi 2nd August 2005 04:46 PM

A simple question
i came across the acronym NOPB while ordering the LM4780 on the national semiconductor website..

What does this stand for..and what does "lead free" mean...


sachi 2nd August 2005 04:51 PM

i guess NOPB stands for 'no lead' with Pb being the notation for lead.

But where is the lead used in the IC package and what advantages do derive when u go for lead free products..

Wombat2 3rd August 2005 07:04 AM

With Europe moving to lead free solder requirement I guess manufacturers are jumping on the "Lead Free" band wagon:xeye:

sachi 3rd August 2005 07:47 AM

can the lead free components be soldered with ordinary solder paste(Sn-Pb)..particularly the LM4780..a friend of mine is offering a couple of them for a nominal amount(3.5$ each). i want to know if i can use it with oridanry solder(Sn-Pb).

DUG 3rd August 2005 02:25 PM

The lead-free label is more complicated for component manufacturers and high volumn (wave soldering surface mount) users.

The lead free solder process requires more heat (higher temperatures) and there is also some changes to packaging as there are special instructions for wave soldering lead free components.

As a DIYer a lead free part will not affect how you use it unless you want to use lead free solder.

Higher temp on the iron is required and the finished solder joint will not have the nice shiny look of a good solder joint normally does with good old 63/37 solder.

For more details go to manufacturer sites like TI and IR.

Hope that helps

PRR 5th August 2005 06:00 AM

> where is the lead used in the IC package

The chip-leads are traditionally plated with a tin/lead alloy so traditional solder will stick well.

> what advantages do derive when u go for lead free products..

You don't have a choice after this year.

Lead is a poison. At solder temperatures, for DIY projects, it is a very weak poison; but you should work in a well ventilated room. In industrial work, hundreds of joints per hour all day every day, lead can accumulate in workers' bodies. A century of working with lead says this is not a BIG problem, but it may be a small problem, and it isn't really necessary to use so much lead in electronics. Europe will soon ban use of lead on electronics. It does not make sense for chip-makers to stock both lead and no-lead parts, so they are all switching to no-lead parts that can be sold everywhere, even in Europe.

I like lead, I grew up snorting leaded gasoline, lead-covered cables, lead-glaze pots, and lots of lead solder. I think heavy drinking (alcohol) does more brain-damage than most industrial uses of lead (not counting lead smelting, large solder-baths, lead-paint factories, and other heavy-lead industries). However, drinking is a personal choice, while lead is forced on workers by employers, so it is reasonable to ban it if possible.

Being a lead-head, I do not like lead-free solders and no-lead chip-leads. It works different, it looks different (and visual inspection was always the way to judge the quality of a soldered joint). But the new ways are not bad, just different.

BTW: I have known children with lead poisoning, and an adult with a severe case of mercury poisoning (different but similar). Heavy-metal poisoning CAN be extremely serious. But DIY soldering is not enough exposure to be a big problem, and is probably one of the least poisonous things you do every day.

> what advantages do derive when u go for lead free products..

You and our children will live in a low-lead world and be less stupid than I am.

DcibeL 5th August 2005 06:22 AM

I am currently working as an electronics assembler until I finish up my schooling. My workplace is slowly moving to lead-free in all our products. I have to say that lad-free is tougher to work with (apart from connectors, everything I work with is surface mount), and the solder joints aren't as good looking. They look like "disturbed" solder or cold solder joints. I'm not a big fan, but I'm sure it just takes a little practice to get used to. I am a big fan of not inhaling lead anymore though :).

So to say the same thing everyone else has said, there is no worries in using a lead-free IC. If you have trouble getting solder to wet to the legs, just wipe a little flux on them.

DigitalJunkie 6th August 2005 09:51 AM

I always get a bad headache if i've been soldering for a while,maybe an hour or more. Those fumes are nasty. :xeye:

AndrewT 6th August 2005 10:12 AM

a face mask would help.
No, not to stop the fumes, to stop you putting contaminated fingers in your mouth! :yuck:
How do we stop ourselves leaning/stooping forward when soldering at the bench and inhaling those fumes? Bending back and trying to solder does not work for me. And that industrial extraction equipment is far too noisy besides taking up too much room. I wish I had installed those concealed pipes in the walls to a remote vacuum cleaner. Missed the chance in this build, OOPs.

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