TO92 alternative footprint

Did you start with a schematic?

As you say you are new to CADsoft, then go to the installation folder and find the DOC folder which contains 'tutorial' amd 'manual'.

These files are great help.

Mogens

Yes, I did start with a schematic.

I read through the documentation. Other than creating or modifying the library files, I don't see how to fix this.

I downloaded the latest Fairchild Library and searched for the component using the element14 product code (1017673) to make I get the correct device. Still, the footprint does not match that of the datasheet or the actual device.

From eagle library you can choose another NPN that has the footprint you want and then use the BC547 when you are ready to plug the transistors into the board.

Good luck,

Mogens

Thanks, that will work for a small circuit as a work around but will result in a lot of manual updates to correct values and mess up the BOM for larger circuits.

Is there a simple (a few clicks) way to correct the library by changing only the footprint, or is up to the supplier of the libraries to update?

Hi jengel,

You can edit the library yourself if you like, and then select Library->Update in the schematic view to perform the update on all such parts in your schematic (and then manually correct any traces you may have already laid out in the PCB view).

However, I think maybe PCB assembly/production may have forming machines for transistors? If this is for a personal project, the pins will be extremely close together, so perhaps it is better to use the existing footprint, and manually form the wires to fit?

Anyway, you can edit the library if this is what you really want to do (but better to create your own library for custom parts like this). This is described in the EAGLE manual.

Thank you shabaz for the reply.

It would seem I'll have to go down the modified library path.

Luckily I don't have to deal with forming machines. I am surprised though at how so many transistors can have the wrong footprint. I would have thought an application so popular (and expensive) would cater for the most common footprint.

On 5/03/2015 9:42 p.m., jengel wrote:

Thank you shabaz for the reply.

 

It would seem I'll have to go down the modified library path.

 

Luckily I don't have to deal with forming machines. I am surprised

though at how so many transistors can have the wrong footprint. I would

have thought an application so popular (and expensive) would cater for

the most common footprint. s

 

I feel this straight leg (low cost) TO92 variant was never intended to

be inserted without forming the legs.

Have look at the dimensions

http://www.onsemi.com/pub_link/Collateral/BC546-D.PDF

Consider how small the lands will be once the hole size and clearance

between pads is considered.

HTH

Warren

Good point, I never thought about the fact that I might have to bend it anyway.