[sdiy] Identifying pin 1 on an SMD IC

[Seb Francis]

Hi Brett,

If you look in the OP275 datasheet it shows the pin-outs of the SOIC 
package.  It's the same as the DIP: pin 1 is top left (or bottom right 
if you have it round the other way).  And according to the outline 
dimensions diagram the SOIC package should have a small semi-circular 
cut-out on the pin 1 end.  Also the left (pin 1) side has more of a 
slope than the other side.  Do yours not have these features?

I wrote a little tutorial on SMD soldering, maybe it's useful for you?
http://burnit.co.uk/sdiy/index.php?page=4xd&subpage=soldering
It's really pretty easy if you have the right techniques.

Seb




Brett Maddaford wrote:
> I picked up some SMD op275's recently for a filtrex im building and
> soldered 1 onto a SMD to DIP adapter last night. When I came to solder
> it I found the only indication of what might be pin 1 was a small white
> arrow pointing to one end of the IC. What I found odd was this arrow
> when held pointing up is actually printed on the right side of the IC
> and not the left where you usually find pin 1. Ok if there were other
> markings on the IC meaning it couldnt be placed in the left side as
> normal i'd think it was just a case of fitting it anywhere there was
> space but there was easily enough room to print it next to the top left
> pin.....I guess i'm just checking could pin 1 possible be the top right
> pin or am i assuming right that the arrow indicates what end of the IC
> has pin 1 and that it is the left top pin as with anything other IC?
> Sorry i hope this isnt a dumb ass question ;)
>  
> Brett
>  
> ohh yeah and this was my first time soldering an SMD and personally i
> hope through hole stays around long enough for most components so i
> never have to do it again ;)
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