MOSFET punch-through
 

Who said power mosfets don't suffer " punch- through" like BJTs do ?

Pics are of an Hitachi 2SK176

Nch lateral, 125 watt, 200 volt, 8amp.




........ Phil

MOSFET punch-through
 

Rather extreme punch-through! I was expecting a pic of a hole in the die.
looks like there was an arc that ate a hole from the source pin through the
TO3 case. Geez! Weird stuff happens when you have enough voltage and seed a
V-field with ions...
Oppie

"Phil Allison" wrote in message
...


Who said power mosfets don't suffer " punch- through" like BJTs do ?

Pics are of an Hitachi 2SK176

Nch lateral, 125 watt, 200 volt, 8amp.




....... Phil

MOSFET punch-through
 

Phil Allison wrote:

Who said power mosfets don't suffer " punch- through" like BJTs do ?

Pics are of an Hitachi 2SK176

Nch lateral, 125 watt, 200 volt, 8amp.



Impressive! How'd you do that?

--
Regards, Joerg

http://www.analogconsultants.com

MOSFET punch-through - ExFets.jpg
 

On Wed, 19 Sep 2007 19:01:38 +1000, "Phil Allison"
wrote:



Who said power mosfets don't suffer " punch- through" like BJTs do ?

Pics are of an Hitachi 2SK176

Nch lateral, 125 watt, 200 volt, 8amp.




....... Phil



TO-247's don't do that. The plastic just comes off in high-velocity
chunks.

John

MOSFET punch-through - ExFets.jpg
 

John Larkin wrote:

On Wed, 19 Sep 2007 19:01:38 +1000, "Phil Allison"
wrote:



Who said power mosfets don't suffer " punch- through" like BJTs do ?

Pics are of an Hitachi 2SK176

Nch lateral, 125 watt, 200 volt, 8amp.




....... Phil




TO-247's don't do that. The plastic just comes off in high-velocity
chunks.


Are those the initials of the guilty ones on there? Something like a
hall of shame display ...?

--
Regards, Joerg

http://www.analogconsultants.com

MOSFET punch-through
 

"Joerg"
Phil Allison wrote:

Who said power mosfets don't suffer " punch- through" like BJTs do ?

Pics are of an Hitachi 2SK176

Nch lateral, 125 watt, 200 volt, 8amp.


Impressive! How'd you do that?


** Was like that when I found it - inside a 1000 watt per ch power amp.

Seems a DC arc started up from the drain pin to the nearest part of the
case, eventually self extinguishing when a large enough hole was burnt
through.

The somewhat overheated drain pin detached from the glass seal leaving the
small hole you see in one pic.

It's a rare event, but I have seen one other similar example and just one
involving a BJT.

The trigger event for the DC arc is the bonding wire from the drain or
emitter pin fusing.




...... Phil

MOSFET punch-through - ExFets.jpg
 

flipper wrote:

On Wed, 19 Sep 2007 08:42:19 -0700, John Larkin
wrote:


On Wed, 19 Sep 2007 19:01:38 +1000, "Phil Allison"
wrote:



Who said power mosfets don't suffer " punch- through" like BJTs do ?

Pics are of an Hitachi 2SK176

Nch lateral, 125 watt, 200 volt, 8amp.




....... Phil



TO-247's don't do that. The plastic just comes off in high-velocity
chunks.

John


Yeah. Looks, unfortunately, familiar.


Oh, you should have seen all the tubes that came to grief in our ham
radio power amps back in the 70's. Some of that was really ugly. At
least one could usually clean it all up with broom and shovel.

--
Regards, Joerg

http://www.analogconsultants.com

MOSFET punch-through - ExFets.jpg
 

Joerg wrote:

flipper wrote:
John Larkin wrote:
"Phil Allison" wrote:

Who said power mosfets don't suffer " punch- through" like BJTs do ?

Pics are of an Hitachi 2SK176

Nch lateral, 125 watt, 200 volt, 8amp.



TO-247's don't do that. The plastic just comes off in high-velocity
chunks.

Yeah. Looks, unfortunately, familiar.

Oh, you should have seen all the tubes that came to grief in our ham
radio power amps back in the 70's. Some of that was really ugly. At
least one could usually clean it all up with broom and shovel.

I have a KT88 here somewhere with a *molten* anode.

Graham

MOSFET punch-through - ExFets.jpg
 

In message , John Larkin
writes
Actually, TO-247s do do that. Compaq 386 PSU with Aluminium case,
IRFP450 devices, they used to punch through the metal back plate and
also through the heatsink they were attached to, often the molten ejecta
solidified and fixed the device firmly to the heatsink.



[ A UUEncoded file (ExFets.jpg) was included here. ]


--
Clint Sharp