K S wrote:
> Hello list.
>
> A warning to all and also looking for feedback of similar past experiences.
>
> I've been using ST L6203 H-bridges on many of my products over the last few
> years. Thousands have gone out without a single issue, ever.
>
> Just the other month I organised a kitting company to supply me the L6203s
> as part of a kit. I assumed they *might* get them from the grey market but
> that was immaterial to me. Then suddenly I started having many failures both
> during testing and in the field. Failures approached 25%! Generally,
> replacing the faulty L6203 with another solved the problem.
>
> I was completely stumped until I noticed that while replacing the parts the
> legs would easily snap off. Then comparing them with older parts obtained
> from the authorised distributor I noticed that the legs had a much duller
> and lacklustre finish, occasional jags (and also occasional whisker-like
> protrusions) and were very brittle. It turns out that most of the failures
> were due to almost invisible mico-cracks in the pins; if i applied solder to
> the pins it would usually fix the problem. This created a nightmare during
> debugging as I'd put the scope probe on the base of the lead not knowing
> that it never reached the silicon inside.
>
>   
This can happen when the devices are stored in an area in which the 
devices are attacked by high heat
and an acidic atmosphere. Probably the metal was simply weakened by 
attack. My guess is that they
were improperly stored.

--Bob

> I don't know whether this is because that batch of parts were RoHS compliant
> (the dull finish may be due to that), the fab that made these (Singapore) is
> a dud or whether they are frauds? I have been assured that the origin of the
> parts was Future in the USA.
>
> Regards, Kris.
>   

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