Electronic component orientation question

August 12, 2020, 02:50 PM

mark123

I have these tiny parts that I can barely see:

The data sheet says "the pin one indicator is in this shaded area" but it doesn't say what the indicator is. There is a printed dot, that looks more like a copyright symbol, and a printed line on opposite ends that would indicate that pin 1 could be on either end. The dot looks more like a dot in the thumbnail pic but up close the line looks more defined.

Here is a closeup:

Any idea what the correct indicator is or should I just solder them in and try it both ways?

August 12, 2020, 02:53 PM

stoic-one

I don't think that is a "copyright symbol", I'm pretty sure that's a molding mark to indicate pin #1, could be wrong.

I HIGHLY recommend against "try it both ways", you'll probably let the smoke out.

Everyone knows the smoke is what makes electronics work...

August 12, 2020, 02:56 PM

ensigmatic

Identifying pin no 1 on an IC

"America is at that awkward stage. It's too late to work within the system,,,, but too early to shoot the bastards." -- Claire Wolfe
"If we let things terrify us, life will not be worth living." -- Seneca the Younger, Roman Stoic philosopher

August 12, 2020, 03:00 PM

mark123

quote:
Originally posted by ensigmatic:
Identifying pin no 1 on an IC

Well, I'll be. I didn't even notice the bevel. Mostly because it's microscopic and partly because I didn't know to look for it. Thanks.

Text direction, a dot-ish mark and a bevel is three against the line so the line loses.

August 12, 2020, 03:04 PM

mark123

quote:
Originally posted by stoic-one:
I don't think that is a "copyright symbol", I'm pretty sure that's a molding mark to indicate pin #1, could be wrong.

I HIGHLY recommend against "try it both ways", you'll probably let the smoke out.

Everyone knows the smoke is what makes electronics work...

Those little beauties are like $7 a piece so I don't want to let the smoke out.

August 12, 2020, 03:38 PM

ensigmatic

Handling bare ICs like that: You are using appropriate anti-static measures, I hope?

August 12, 2020, 03:50 PM

mark123

quote:
Originally posted by ensigmatic:
Handling bare ICs like that: You are using appropriate anti-static measures, I hope?

I have a grounded anti-static mat.

August 12, 2020, 04:13 PM

ensigmatic

quote:
Originally posted by mark123:
quote:
Originally posted by ensigmatic:
Handling bare ICs like that: You are using appropriate anti-static measures, I hope?
I have a grounded anti-static mat.

You need to be wearing an anti-static wrist band, connected to the mat, as well. Something such as shown here: SCS 746

And the mat needs to be grounded with a similar cable. N.B.: Those cables have high-value resistors built-in. They ARE NOT low-resistance connections. Using just wire would create an electrocution hazard.

Modern ICs are so-densely packed, the internal components so small and the paths between them so short, it takes very little ESD to impair or destroy them.

August 12, 2020, 04:15 PM

mark123

quote:
Originally posted by ensigmatic:
quote:
Originally posted by mark123:
quote:
Originally posted by ensigmatic:
Handling bare ICs like that: You are using appropriate anti-static measures, I hope?
I have a grounded anti-static mat.

You need to be wearing an anti-static wrist band, connected to the mat, as well. Something such as shown here: SCS 746

And the mat needs to be grounded with a similar cable. N.B.: Those cables have high-value resistors built-in. They ARE NOT low-resistance connections. Using just wire would create an electrocution hazard.

Modern ICs are so-densely packed, the internal components so small and the paths between them so short, it takes very little ESD to impair or destroy them.

I have an anti-static wrist band ... somewhere around here.

August 12, 2020, 06:18 PM

mark123

I should be more concerned with the moisture sensitivity of these things. I moved them to the safe by the heater until my PCBs come in.

August 12, 2020, 10:58 PM

nhtagmember

the dot indicates Pin 1 for orientation

August 12, 2020, 11:20 PM

ensigmatic

quote:
Originally posted by mark123:
I should be more concerned with the moisture sensitivity of these things. I moved them to the safe by the heater until my PCBs come in.

Static is a far bigger issue than moisture.

If you have that wrist band and the proper cable to go with it, I strongly advise you find and use them.

I won't even take a populated PCB out of its static-resistant or anti-static packaging w/o first deploying a mat, putting on a wrist band, and tying mat, wrist band, and item under repair/upgrade/assembly together.

You would be amazed at how much static electricity can be generated with the most innocuous of movement, and it doesn't have to be nearly enough to generate a noticeable spark to cause damage.

August 13, 2020, 03:46 AM

mark123

quote:
Originally posted by ensigmatic:
quote:
Originally posted by mark123:
I should be more concerned with the moisture sensitivity of these things. I moved them to the safe by the heater until my PCBs come in.

Static is a far bigger issue than moisture.

If you have that wrist band and the proper cable to go with it, I strongly advise you find and use them.

I won't even take a populated PCB out of its static-resistant or anti-static packaging w/o first deploying a mat, putting on a wrist band, and tying mat, wrist band, and item under repair/upgrade/assembly together.

You would be amazed at how much static electricity can be generated with the most innocuous of movement, and it doesn't have to be nearly enough to generate a noticeable spark to cause damage.

The packaging says to bake them for 24 hours at 125° before soldering. I've never worked with SMD before. I've also never had to worry about popcorning a component. Just trying something new.