Technology and package

Marco Trapanese schrieb:

EAGLE assumes that any part name is composed in the following way:

 

BASE_NAME|TECHNOLOGY|PACKAGE

 

some parts come with another order:

 

BASE_NAME|PACKAGE|TECHNOLOGY

 

How to handle this?

IMHO, the "technology" is absolutely senseless/useless anyway. You get

the same effect just by setting a proper VALUE.

So all my libraries contain devices that are as generic as possible, and

none of them uses "technology". When putting them into the schematic, I

assign a meaningful value, and all is done.

Tilmann

Il 08/04/2013 13:44, Tilmann Reh ha scritto:

IMHO, the "technology" is absolutely senseless/useless anyway. You get

the same effect just by setting a proper VALUE.

 

So all my libraries contain devices that are as generic as possible, and

none of them uses "technology". When putting them into the schematic, I

assign a meaningful value, and all is done.

My experience is different than yours. The technology field (since EAGLE

supports the "append" features for pin/pad) is very useful for me to

take care of the small differences among parts.

For example the C/I designator for temperature ranges is properly

handled with the technology fields, allowing you to have ONE part in the

library. Or think about an LDO or TVS family: they could have dozen of

different voltages. Each one with its own order code.

If you don't use the technology fields you must create a different part

for every variant!

The best would be to define the "part name" according to the

manufacturer specifications. But I admit this could be quite complex to

implement.

Marco

Marco Trapanese schrieb:

IMHO, the "technology" is absolutely senseless/useless anyway. You get

the same effect just by setting a proper VALUE.

 

So all my libraries contain devices that are as generic as possible, and

none of them uses "technology". When putting them into the schematic, I

assign a meaningful value, and all is done.

 

My experience is different than yours. The technology field (since EAGLE

supports the "append" features for pin/pad) is very useful for me to

take care of the small differences among parts.

 

For example the C/I designator for temperature ranges is properly

handled with the technology fields, allowing you to have ONE part in the

library. Or think about an LDO or TVS family: they could have dozen of

different voltages. Each one with its own order code.

 

If you don't use the technology fields you must create a different part

for every variant!

That's exactly what is not necessary.

Different temperature ranges, different regulator voltages etc. can

perfectly be handled just with different VALUES.

For example, a generic voltage regulator is "78xx", for any 7800 series

(or similar) three-pin positive regulator - with package variants for

TO220 (vertical and horizontal), TO92, DPAK, D2PAK etc..

In the schematic, simply pick it (with the right package variant), then

assign the proper value (like 7805, 78L12 - or even LP2950-3.3).

Or, for TVS diodes: we use one single device, with a few package

variants (some common THT sizes, SMA, SMB, SMC) - and then set a proper

value (like P6SMB15CAT3GP6SMB15CAT3G, for example).

Of course you need to take care - don't assign an LP2950 to a TO220

package. But as developer, you need to take care anyway, and for much

more subtle details...

The best would be to define the "part name" according to the

manufacturer specifications. But I admit this could be quite complex to

implement.

No, it's quite easy: use the part name provided by the manufacturer AS

VALUE.

Tilmann

Marco Trapanese schrieb:

In the past I did exactly that.

It was fine until I had to go in production. Who mounts the boards ask

me not only the part value but also the order codes from suppliers

(Farnell, Mouser, Digikey).

I store them in the attributes and the BOM is ready in a while.

 

Following your method I must write the order codes every time by hand.

Yes. However, very many standard components don't require special order

codes for particular suppliers - you buy them where you get them (or

where you place an order anyway). So creating a BOM isn't that hard (we

also use an ULP that does most of the work). There always are only a few

parts that really need to be specified in more detail.

Otherwise, you need trillions of different devices for basically the

same part. Just one more example: a simple 470/35 capacitor, for me it's

just a 10 mm diameter part. Depending on the circuit, it needs to be a

standard capacitor (brand doesn't matter), or some special low-ESR type,

or eventually a special high-temperature type. Sometimes, height also is

an issue. Using attributes and order codes, you'd need about a dozen

different devices just for this single capacitor (and the same amount

for every other C/U combination) - while opposed to this, our generic 10

mm device suits about a dozen different C/U combinations including all

particular types and brands (which are remarked in the value, if necessary).

Finally, it's your decision if you want to put more effort on creating a

BOM - or on maintaining bloated libraries and keeping the design files

in sync with them.

Tilmann

Il 08/04/2013 15:10, Tilmann Reh ha scritto:

That's exactly what is not necessary.

 

Different temperature ranges, different regulator voltages etc. can

perfectly be handled just with different VALUES.

 

For example, a generic voltage regulator is "78xx", for any 7800 series

(or similar) three-pin positive regulator - with package variants for

TO220 (vertical and horizontal), TO92, DPAK, D2PAK etc..

In the schematic, simply pick it (with the right package variant), then

assign the proper value (like 7805, 78L12 - or even LP2950-3.3).

 

Or, for TVS diodes: we use one single device, with a few package

variants (some common THT sizes, SMA, SMB, SMC) - and then set a proper

value (like P6SMB15CAT3GP6SMB15CAT3G, for example).

In the past I did exactly that.

It was fine until I had to go in production. Who mounts the boards ask

me not only the part value but also the order codes from suppliers

(Farnell, Mouser, Digikey).

I store them in the attributes and the BOM is ready in a while.

Following your method I must write the order codes every time by hand.

Am I wrong?

Marco

René König schrieb:

Different temperature ranges, different regulator voltages etc. can

perfectly be handled just with different VALUES.

 

And the ATTRIBUTEs are probably different as well, or do you even have a

generic ATTRIBUTE-set? Or don't you use ATTRIBUTEs at all? I simply

cannot imagine me entering all the necessary ATTRIBUTEs over and over

again...

Exactly: I also don't use attributes at all.

KISS principle.

Tilmann

René König schrieb:

Different temperature ranges, different regulator voltages etc. can

perfectly be handled just with different VALUES.

 

And the ATTRIBUTEs are probably different as well, or do you even have a

generic ATTRIBUTE-set? Or don't you use ATTRIBUTEs at all? I simply

cannot imagine me entering all the necessary ATTRIBUTEs over and over

again...

Exactly: I also don't use attributes at all.

KISS principle.

Tilmann