How to interpret SOA graphs?

[Wong Sy Ming]

I'm looking to run some NTY100N10 devices in linear mode for the pass
element in a DC power supply, but it seems that these devices have a very
poor power dissipation capability? Or do I not know how to interpret the SOA
graph?

 

[Ted Wilson]

The ratings shown on the graph are for the device on its own, without any
form of heatsink. (6W with a theta j-a of 25 deg C gives a junction temp
rise of 150C).

Depending on the size of heatsink you're prepared to use, you can squeeze
considerably more out of it.

Regards

Ted Wilson

 

[Ted Wilson]

Hi

The question was specifically about power consumption, as opposed to SOA in
general.

I'm puzzled by your reference to current crowding at high voltage. This
seems to be an allusion to the phenomenon that occurs in bipolars causing
'second breakdown'. This doesn't occur in power mosfets, due to the ptc of
Rd-s on.

If there's omething else goes on, I'm interested to hear about it.

Regards

Ted Wilson

 

[mike]

Hi

The question was specifically about power consumption, as opposed to SOA in
general.

Sorry, I read the Subject line and interpreted that to mean you were
asking "How to interpret SOA graphs?". My mistake.

mike

I'm puzzled by your reference to current crowding at high voltage. This
seems to be an allusion to the phenomenon that occurs in bipolars causing
'second breakdown'. This doesn't occur in power mosfets, due to the ptc of
Rd-s on.

If there's omething else goes on, I'm interested to hear about it.

Regards

Ted Wilson

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