[[email protected]]

I'm looking for information how a (2N2222 typ ) die can be
attached to a pc board to provide a low thermal path and am looking
for info on analyzing the thermal path and what material to use to
hold the die to the board.

I've done a google search but likely have not used the right terms
touse for the search.

Any suggestions would be appreciated.

Harry

 

[Jim Thompson]

I'm looking for information how a (2N2222 typ ) die can be
attached to a pc board to provide a low thermal path and am looking
for info on analyzing the thermal path and what material to use to
hold the die to the board.

I've done a google search but likely have not used the right terms
touse for the search.

Any suggestions would be appreciated.

Harry

Are you truly asking about DIE? If so, there are metal-filled epoxies
used for such DIE mount.

...Jim Thompson

 

[Eeyore]

I'm looking for information how a (2N2222 typ ) die can be
attached to a pc board to provide a low thermal path and am looking
for info on analyzing the thermal path and what material to use to
hold the die to the board.

I've done a google search but likely have not used the right terms
touse for the search.

If you could explain what you're trying to acheive it might help.

Is it that you have a need to have the die closely thermally coupled to the pcb
? The more normal alternative if needing to dissipate more power than the
package offers is to select a larger device !

Graham

 

[Robert Baer]

I'm looking for information how a (2N2222 typ ) die can be
attached to a pc board to provide a low thermal path and am looking
for info on analyzing the thermal path and what material to use to
hold the die to the board.

I've done a google search but likely have not used the right terms
touse for the search.

Any suggestions would be appreciated.

Harry

Nominaly, transistor die are soldered to a metal pad (or the can if a
metal case).
So do the same thing: die attach using (high temp) solder.
Please do not ask what alloy is used, becasue (so far) nobody is talking.
BTW, you cannot get blood (better power rating, better sat, etc) out
of a turnup (the crappy *low* power *signal* 2N2222).
The damn thing is a resistor above "reasonable" currents (say in the
100mA region)!

 

[Robert Baer]

Are you truly asking about DIE? If so, there are metal-filled epoxies
used for such DIE mount.

...Jim Thompson

More expensive and less reliable than solder.

 

[Robert Baer]

If you could explain what you're trying to acheive it might help.

Is it that you have a need to have the die closely thermally coupled to the pcb
? The more normal alternative if needing to dissipate more power than the
package offers is to select a larger device !

Graham

Absolutely! Like a 2N3055.

 

[Chris Jones]

More expensive and less reliable than solder.

Most plastic packaged ICs seem to be attached to their leadframe using
conductive epoxy. There must be some reason for doing it this way. One
popular brand is Ablestik.

Chris

 

[Robert Baer]

Robert Baer wrote:




Most plastic packaged ICs seem to be attached to their leadframe using
conductive epoxy. There must be some reason for doing it this way. One
popular brand is Ablestik.

Chris

Maybe because the die attach area is to small to work with?

 

[maxfoo]

I'm looking for information how a (2N2222 typ ) die can be
attached to a pc board to provide a low thermal path and am looking
for info on analyzing the thermal path and what material to use to
hold the die to the board.

I've done a google search but likely have not used the right terms
touse for the search.

Any suggestions would be appreciated.

Harry

'Molytabs'(Molybdenum metal)are usually used as a pedestal for the die. Then
held together with silver epoxy. Most commonly used on alumina substrates...

 

[Jim Thompson]

Most plastic packaged ICs seem to be attached to their leadframe using
conductive epoxy.

Not so, most _IC_ die-bonds are eutectic.

There must be some reason for doing it this way. One
popular brand is Ablestik.

Chris

Most chip bonds to _PCB_ ARE epoxy.

...Jim Thompson

 

[Chris Jones]

Not so, most _IC_ die-bonds are eutectic.


Most chip bonds to _PCB_ ARE epoxy.

...Jim Thompson

Perhaps I was wrong when I said most, however certainly hundreds of millions
of plastic packaged ICs use conductive epoxy, for example LFCSP packages at
least. I don't know about older dual in line packages etc.

Chris

 

[Jim Thompson]

Perhaps I was wrong when I said most, however certainly hundreds of millions
of plastic packaged ICs use conductive epoxy, for example LFCSP packages at
least. I don't know about older dual in line packages etc.

Chris

Hmmm! I've not noted that, but will take your word for it, for I
don't know for sure.

...Jim Thompson