MRF300AN

[kopcicle]

I have some reading material for you.

https://qrpblog.com/2019/10/a-600w-broadband-hf-amplifier-using-affordable-ldmos-devices/ $379
https://qrpblog.com/product/f600-160m-4m-600w-low-pass-filter-kit/ $249
https://qrpblog.com/product/b1500-rf-amplifier-backpanel-unit/ $119
$747
https://www.hamradio.com/detail.cfm?pid=H0-005150 $1,099.95
https://www.rfparts.com/tubes/tubes-811a.html $27 EA* x4
https://www.rfmw.com/products/detail/mrf300an-nxp/618411/
https://www.nxp.com/docs/en/data-sheet/MRF300AN.pdf $25.77 ea x2

So yeah, you still have to put a box around it and it doesn't glow in the dark. Then there's the little thing about needing a bunch of 50 volt current. If it does let the smoke out it's $54 for the pair. That's 600 watts from two 50V devices. It's time to move along.

*RFP isn't listing matched quads for some reason.

 

[Handy Andy]

You are aware that they are GSD or DSG not GDS - like the BCE BJT's - and Digikey have them shooting thru the roof in $$$.

 

[Handy Andy]

A lot of Texans remember the Alamo...

Many HR-2510 owners remember the MRF-477 - this device can work with that...

BEC to GSD

 

[Shockwave]

You are aware that they are GSD or DSG not GDS - like the BCE BJT's - and Digikey have them shooting thru the roof in $$$.

That is so the metal tab on the back of the transistor can be at DC ground and attached directly to the heatsink without any insulator. This is not only important for better heat transfer at higher power levels, it also helps this inexpensive package obtain a lower source inductance path to ground. That helps with amplifier stability on the higher frequencies.

What you mention is critical when using this part to replace another. However, being a new 50 volt device, most applications will be in new designs.

 

[Shockwave]

I have some reading material for you.

https://qrpblog.com/2019/10/a-600w-broadband-hf-amplifier-using-affordable-ldmos-devices/ $379
https://qrpblog.com/product/f600-160m-4m-600w-low-pass-filter-kit/ $249
https://qrpblog.com/product/b1500-rf-amplifier-backpanel-unit/ $119
$747
https://www.hamradio.com/detail.cfm?pid=H0-005150 $1,099.95
https://www.rfparts.com/tubes/tubes-811a.html $27 EA* x4
https://www.rfmw.com/products/detail/mrf300an-nxp/618411/
https://www.nxp.com/docs/en/data-sheet/MRF300AN.pdf $25.77 ea x2

So yeah, you still have to put a box around it and it doesn't glow in the dark. Then there's the little thing about needing a bunch of 50 volt current. If it does let the smoke out it's $54 for the pair. That's 600 watts from two 50V devices. It's time to move along.

*RFP isn't listing matched quads for some reason.

With today's switching power supplies, coming up with 50 volts is often easier than building a good HV plate supply. Plus it will be regulated and usually has adjustable current limiting.

I'm also seeing most of these modern RF linear power MOSFETS are not really requiring matching with gate thresholds typically within a few tents of a volt when pulled from the same lot. While this difference cannot just be ignored, it is easily compensated for, by installing independent bias adjustments for each transistor.