From: "Frank Bemelman"
Subject: Re: What are these terms in PCB design?
Date: Thu, 3 Oct 2002 23:32:28 +0200
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Organization: EuroNet Internet
NNTP-Posting-Date: 03 Oct 2002 21:35:10 GMT
"Spehro Pefhany" schreef in bericht
> The renowned Ban wrote:
> > Well, inside the LED there are two leads, one (the negative) is directly
> > connected to the little metal reflector where the die is soldered to,
> > whereas the other is bonded with a tiny wire to the top of the die.
> Actually they can be either way. Which has fooled more than one assembler.
> I use a silk-screen donut (to guide the long positive lead which is on
> LEDs that we order) and a keyed outline silkscreen.
We have used leds from Siemens (or is it infineon, or osram) SFH484 and
changed to SFH486 (both 5mm led). They look the same, but the 486 has a
long lead as cathode, and this is also located on the round side. The
anode is on the flat side of the led. With the 484 it is the other way
round, the long one is anode, and is on the flat side of the led. The
idiot at Siemens who did this SFH486 ought to be hanged *AND* shot.
2500 leds soldered in the wrong way. Were removed and placed again.
Wrong again !!! Okay, somebody else ought to be hanged and shot for
I changed the footprint for this led so that both pads are round (I used
to use a square one for the long positive lead) and a round 5mm circle for
the silkscreen, removed that flat side. So now it is a mystery how to
mount the leds, and the assembler will use the example board to check
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