How to tell which pin is #1 on IC chip

Thread Starter


Joined Dec 13, 2007
I am new to this, and I dont know which pin on my CD40192 IC chip is pin 1.

Here is what the chip looks like:

Is pin number one next to the little half moon shape, or next to the circle on the other side?


Joined Jul 17, 2007
The end with the bite out of it :)

Also, in most cases if the printing on the top of it is readable (ie: right-side up) the pin on the lower left is #1 - and in more cases, there is either a raised bump or a divot adjacent to #1.


Joined Dec 23, 2006
The two identifiers are either that notch, which indicates the top, or a small circular indent in the top left corner (or both). Top left of an IC is where your standard pin 1 is.


Joined Jun 30, 2006
Good question. If they follow standards you can do what Salgat says on most. Of courst they like to put FOUR DAMNED indents on the chip with one being 0.0000000000000001decimillimeter smaller than the others.

On square chips it can be somewhere near the angled corner OR in the middle of one side of the fing chip. Of course they wear the die out and all the corners look rounded and the case material has oozed out.

On some they put a bevel. No indent, no dot nothing though sometimes it has dots ON BOTH SIDES. Of course they've made 15 billion of the chips so the die is worn out and the top looks like a bent sheet of paper.

Easiest method is to go get the data sheet and look the outline drawing. Eventually you will have most of the standard ones memorized.

The next gen of chips you'll have to buy a tool to tell you how it goes because you won't be able to SEE the part!!!