Custom Symbol for IC with no pin labels

I'm working on a circuit that includes an MCP23018 I/O Expander. Here's a photo of the IC:

As you can see the pins aren't labeled. You have to figure out which end is which by looking at the little half-circle cutout on one end.

I'd like to be able to add a corresponding half-circle in my custom symbol. Or, barring that, I'd like some way to indicate which end is the half-circle end.

by erincalling
June 27, 2017

All DIP (dual in-line package IC chips) are assumed to be the same as far as pins are concerned. For example, lets use a 8 pin dip chip. Put the dimple on the left and start counting at the bottom left counter clockwise around to the top row. Numbers are: right to left: 1,2,3,4, then right to left on top: 5,6,7,8.

Read a few magazines about electronics, you can pick up a lot there.

If you look for DATA SHEETS online, you will see what I refer to. Good luck.

by Russ7411
June 27, 2017

Thanks for that suggestion, Russ. I don't think it's what I need, though. I'm labeling the pins by name (VSS, VDD, etc.), not numbers. I'm also hoping this schematic can be used by amateurs who may not know that convention.

by erincalling
June 28, 2017

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