EMRFD Message Archive 5645

Message Date From Subject
5645 2011-01-03 02:02:24 brainerdd QRO FET
Freescale has announced a new device that looks real good for QRO operation. The MRFE6VP61K25 is 2 LDMOS FETS on a single die. It is rated for 1.8 to 600 MHz operation. It is rated for 1250 watts of CW output into an SWR as high as 65 to 1. It is rated for 50V operation. At 230 MHz, it has a gain of 24 dB at 1250 watts output with 50 V on the drain. Likely even higher gain at HF. That means less than 6 watts in = 1250 watts out!
Digikey lists them as in stock and $270.90 each.

Dave - WB6DHW
5646 2011-01-03 04:41:07 w4zcb Re: QRO FET
You might wish to take a look at the link.



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5647 2011-01-03 04:56:11 Robert Bennett Re: QRO FET
That means less than 6 watts in = 1250 watts out!

Hmm.......I guess getting 1250Watts of RF out is going to be lot easier than
shifting 1KW+ heat!!

73 Robert
5651 2011-01-03 10:08:25 Jim Miller Re: QRO FET
I wonder what Freescale recommends as heat sink arrangement. I would think
they would have something if for no other reason to demonstrate performance
in their datasheet.

jim ab3cv

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5652 2011-01-03 16:07:19 kb1gmx Re: QRO FET
The usual deal is a .25 inch (or thicker) copper plate backed up by a big heat sink possibly fan cooled to keep it smaller.

The slab of copper is to spread the heat from the small area of the transistors and couple it to the aluminum heat sink.

I'm doing a BLF278 (gemini VHF FET) 2M amp expected to do 350W out and about 600W in so thats the soluti
5653 2011-01-03 17:15:47 R Wall Re: QRO FET
A good place to purchase electrical copper bus bar is a metal scrap dealer. Or a electrician or Switch Board manufacturer.

Roderick Wall, vk3yc.