I'm just starting to learn Eagle and attempting my first PCB layout project, but I'm having trouble with one part. I've found custom libraries for every other part I've needed so far, but can't find anything for the Honeywell SS495A (hall effect sensor) that I need to use.

I found what appears to be a good tutorial on how to make my own library for it. I would try making a library except that the data sheet dimensions only show the device itself, but not what the ideal surface mount pad configuration is (also available in the data sheets for other surface mount components I've been working on.)

Here are the dimensions shown in the data sheet:


This is a link to the full data sheet.

If anyone can point me in the right direction to either find an existing library that would work for this, or to help me determine the appropriate pad layout for a custom library, I'd appreciate it.

Thanks,
Eric

 

That is indeed unfortunate. Some companies put the recommended pad arrangements for their various packages in a separate datasheet. Have you checked whether Honeywell did that? As an alternative, you may find a decent match in ref-packages.lbr Checking very quickly, it looks like almost anything with 0.05" on-center pads (e.g, almost any SOIC pad arrangement) will work. Obviously, you want the pad a little wider than the pin, so an SOIC with 0.03 wide pads might not be too bad. If you are not using a solder mask, you could change the pads to make them a little narrower, but I don't think that will be necessary.

John

 

The dimensions are shown in the data sheet.

All you need are three pads on 0.050" centers.

 

John, I found several other Honeywell docs with the same info, but none that included the pads. Thanks for giving me an idea of what to try for pad sizing.

Mr Chips, sorry, but it's my first time dealing with surface mount components and I had no idea how the pad size should compare to pin size. I did see the component and pin dimensions, but didn't know how much larger in each direction the pads should be.

Thank you both for your help. I'll take a crack at my first custom library object now...

 

If you check a typical SOIC8 device (pick any device, even a 555), you will find the typical increase in pad width to allow a reasonable error in positioning. Center-to-center distance is fixed. Pad length is not so important, within reason, so long as the pads are a little longer than the device's legs are wide. (Watch out for center connections, such as heat sinks.) I often lay down a similar device and then "cheat" with the Information button to edit such things as pad dimensions. That is a lot easier than drafting something de novo. When I must do something de novo, I still check and adjust dimensions using that function. IMHO, it really should be called "Edit."

Eventually, the command language comes into play, but for very occasional users, like myself, or new users, that language can be cumbersome.

John

 

Simple. You've got 0.050" center-to-center.
If you allow 0.015" gap, make each pad 0.035" wide. Make the length 0.070"

 

Thank you both very much!

 

Maybe you can find sparkfun's library which base on eagle.they share it on the github.you can search it by keyword.