I've got a pair of NTE3086 optoisolators in 8-pin DIP packages, and I can't figure out where pin 1 is. There's no dot near any corner, nor does either end have any sort of notch. All there is to distinguish one side from the other is a ridge molded into one of the long edges on top of the package, below the lettering. Has anyone seen a package like this before and can state with some certainty whether the ridge is marking pins 1-4 or pins 5-8? I'm hoping to have a response this evening so I can finish my project and test it out, but I'm not plugging in those chips without knowing the correct orientation.

For the record, the datasheet shows a dot AND a notch, but no ridge, and no indication that the lettering is always put on the same way.

 

If you have a meter with a diode check, you can identify the LED's easily.

 

I can never seem to get a reading with the diode-check function of my DVM, but maybe one of the ones in our avionics lab will do better. Good idea, I should've thought of that myself.

 

Whoa, good call, dude! I just checked both chips, and the LEDs (pins 1-4) are definitely on the side with the molded ridge. (doing happy dance in lab)

 

Hello,

Here ia the datasheet.

Greetings,
Bertus

 

Hello,

Here ia the datasheet.

Greetings,
Bertus

I already have the datasheet. The problem is, the chips are not marked as the datasheet or the package picture them (no pin 1 dot, no notch, just this odd molded ridge down one long edge).

 

Hello,

As you see the diodes are at one side of the package.
Here is a way to measure the diodes inside the package.
http://www.allaboutcircuits.com/vol_3/chpt_3/2.html

Greetings,
Bertus

 

I got an email back from NTE this morning with a link to this FAQ page showing their DIP packages.

http://www.nteinc.com/faqs/question13.html

Of course, thanks to the suggestion by "beenthere" I already had my answer within a half hour of my original post. Wish I'd thought to post my question the night before when I realized I couldn't install my chips yet, would've helped my mood Monday morning.