Custom SMD pads

Jay Beritz wrote:

Bert Menkveld wrote:

Jay Beritz wrote:

Jay Beritz wrote:

How can I create a custom SMD pad in Eagle like the one in the

image I attached?

 

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Doesn't someone know how to do this? Please help

 

I'm afraid you're not getting a response because there's no simple

way to do this.  Eagle does not provide any facility for arbitrary

shapes of SMD pads. You could draw a polygon, but Eagle does not

really support the use of polygons in library parts, so this will

involve a great deal of trouble. If you want an SMD with one end flat and

the other rounded, you

could lay two short SMD pads on top of each other, one rectangular

and one rounded. This will give you endless DRC errors, but could

give you the SMD pad shape you want.

 

Do you really need this appearance of SMD pad?  What's wrong with

rounding both ends, or just keeping both ends square?

 

--

Bert Menkveld

 

 

I assumed the IC's pads and the traces on the board must match.

If the trace on the board is touching an area on the IC that is not a

pad won't this heat up the chip or cause other problems?

If you look at the SMD IC package, you'll see that is has metal leads that

are bent down to provide a small length of lead that sits on the pad on the

board.  The rest of the IC package is plastic (non-conductive), and normally

doesn't even touch the board.  You can therefore run traces from the pad

underneath the package without any problems.  The pads themselves can have

square or rounded corners, as different designers and different assembly

procedures may prefer, but for DIY assembly, I don't think it matters.

Take a look at some of the standard SMD footprints in the Eagle libraries to

see how foorprints are typically done.

--

Bert Menkveld

Jay Beritz wrote:

Bert Menkveld wrote:

Jay Beritz wrote:

Jay Beritz wrote:

How can I create a custom SMD pad in Eagle like the one in the

image I attached?

 

------------------------------------------------------------------------

 

Doesn't someone know how to do this? Please help

 

I'm afraid you're not getting a response because there's no simple

way to do this.  Eagle does not provide any facility for arbitrary

shapes of SMD pads. You could draw a polygon, but Eagle does not

really support the use of polygons in library parts, so this will

involve a great deal of trouble. If you want an SMD with one end flat and

the other rounded, you

could lay two short SMD pads on top of each other, one rectangular

and one rounded. This will give you endless DRC errors, but could

give you the SMD pad shape you want.

 

Do you really need this appearance of SMD pad?  What's wrong with

rounding both ends, or just keeping both ends square?

 

--

Bert Menkveld

 

 

I assumed the IC's pads and the traces on the board must match.

If the trace on the board is touching an area on the IC that is not a

pad won't this heat up the chip or cause other problems?

If you look at the SMD IC package, you'll see that is has metal leads that

are bent down to provide a small length of lead that sits on the pad on the

board.  The rest of the IC package is plastic (non-conductive), and normally

doesn't even touch the board.  You can therefore run traces from the pad

underneath the package without any problems.  The pads themselves can have

square or rounded corners, as different designers and different assembly

procedures may prefer, but for DIY assembly, I don't think it matters.

Take a look at some of the standard SMD footprints in the Eagle libraries to

see how foorprints are typically done.

--

Bert Menkveld