Extremely rugged 1,200-W RF MOSFET survives live short circuits and open outputs

[W9GB]

Elector magazine

The first indestructible transistor?
Extremely rugged 1,200-W RF MOSFET survives live short circuits and open outputs
http://www.nxp.com/#/pip/pip=[pip=BLF578XR]|pp=[t=pip,i=BLF578XR]|
Publication date: 22 July 2011

Semiconductor manufacturer NXP is mighty proud of its new high-power transistor, called BLF578XR, which is good for 1.2 kilowatts of RF power output.
The device is suitable for use in RF amplifiers operating in the 10 MHz to 500 MHz frequency range and has proved it’s up against extremely adverse operating conditions.

NXP is so proud of their latest result of outstanding engineering achievement that they released a video demonstrating
the load disconnected and even the output shorted with the RF amplifier in full operation, without so much as harming the transistor.
Typical applications for this power semiconductor include the control of industrial lasers, etc.

YouTube video - Ruggedness tests
http://www.youtube.com/watch?v=8ziYqjMQGEQ

BTW, note that NXP was using an external cooling unit under
the copper spreader in the ruggedness testing video.

w9gb

[AF6LJ]

Impressive It will be nice to see these devices become available.
According to the link the device is still under development.

I have to wonder why the lower frequency limit is so high.

One more comment............
While that test jig had a considerable peace of copper to soak up the energy you couldn't run it for very long in that test jig.

[WB0LSR]

I would think they could be used at lower frequencies, but not having tried I can't be sure. The enhanced ruggedness devices being made these days are impressive to say the least, but I have my doubts as to whether they would be seemingly indestructible at 1.2kW continuous duty, such as what is frequently seen running digital modes.

[AF6LJ]

I would think they could be used at lower frequencies, but not having tried I can't be sure. The enhanced ruggedness devices being made these days are impressive to say the least, but I have my doubts as to whether they would be seemingly indestructible at 1.2kW continuous duty, such as what is frequently seen running digital modes.

I totally agree;
It is possible to create conditions where the drain current would exceed the rated drain current, then you have a fuse not a transistor. What they imply though is as long as you don't exceed the drain voltage and current limits and there is a low resistance thermal path to an efficient radiator or water cooling system it's not possible to destroy this device. As long as the cost you are limited to in terms of a finished product isn't too low their claim is quite realistic.

[AB3FL]

They were not running it at full power during any of the tests. For example, during the short circuit 55V@9.5A = 522 watts INPUT power so somthing was limiting the current somewhere. Also I wonder how much one of them costs. The spec sheet says 75% efficient, so for 1200W out, it would need 1600W in and at 50V that would be 32A. I wanna see it handle a short at those numbers.

Tom - AB3FL

[VE3IYB]

While not the BLF578XR currently in development, the BLF578 is currently available from: http://www.newark.com/nxp/blf578-112/n-ch-hf-vhf-power-ldmos-50v-10mhz/dp/70R2785?CMP=AFC-HEARST at a cost of ~$275USD Same specs, looks like you can order samples too. :)

de VE3IYB Doug EN93ui ~ 60 miles SW of Toronto, Ontario, CANADA Eh?

[WA7PRC]

Semiconductor manufacturer NXP is mighty proud of its new high-power transistor, called BLF578XR, which is good for 1.2 kilowatts of RF power output.
Thanks. I'll pass the info along to my company's RF engineering manager, in case he missed it. We've found that, when you get to the kilowatt level, air-cooling in a reasonably-small package becomes more difficult. MOST of our ≥ 1KW RF sources are water-cooled.