Cree 1700 Volt SiC mosfet

[John K5PRO]

This was posted over at the class E forum:

Cree has introduced a 1700 volt 4.9 Amp silicon carbide mosfet. The C2M1000170D is for high speed/voltage switchmode supplies. I wonder if it would make a nice high power RF device in class E. It only has 69 watts dissipation rating in TO247-3 case. What the heck is that about?
Cin is 191 pF, Cout is 12 pF. 46 nS rise time.

[W3GMS]

Hi John,

Looks like not the best choice for a Class E rig.  The data sheet attached only shows a 2.6A maximum drain current rating, not to mention a horrible Rds figure.  Not sure how the input capacitance compares to other commonly used devices for class E operation. 

It appears this device is primarily targeted for low power auxiliary supplies operating off a Very high voltage rail.  Most of the Class E rigs operate off a bulk voltage considerable lower where more current needs to handled by the switching device.   

Just looking quickly some of Cree's lower voltage parts could be an option.

Joe, GMS

[WD5JKO]

  Over at the shop we use the IX YS DE 475 102 N21A. A pair of these in parallel loaf along at 3KW RF out, class E with resonant sine wave drive. This is at 13.56 Mhz. It takes about 190V DC @ ~ 19 amps supply voltage to get there. I'd estimate the efficiency is mid 80's % if not a little higher. The sine wave drive hurts efficiency a bit. They are around $50-60 apiece.



Jim
WD5JKO

[W3GMS]

 Over at the shop we use the IX YS DE 475 102 N21A. A pair of these in parallel loaf along at 3KW RF out, class E with resonant sine wave drive. This is at 13.56 Mhz. It takes about 190V DC @ ~ 19 amps supply voltage to get there. I'd estimate the efficiency is mid 80's % if not a little higher. The sine wave drive hurts efficiency a bit. They are around $50-60 apiece.
A single one of these on 20M AM, and you could be as strong as K1KW.  
Jim
WD5JKO

Jim,
That device is quite a bit different than the one John mentioned. 
Joe, GMS

[steve_qix]

 Over at the shop we use the IX YS DE 475 102 N21A. A pair of these in parallel loaf along at 3KW RF out, class E with resonant sine wave drive. This is at 13.56 Mhz. It takes about 190V DC @ ~ 19 amps supply voltage to get there. I'd estimate the efficiency is mid 80's % if not a little higher. The sine wave drive hurts efficiency a bit. They are around $50-60 apiece.
Jim
WD5JKO

If I were building an AM rig with 2 of those MOSFETs, I'd run the carrier at around 45 to maybe 50V at 5A to 6A for the pair, with the power supply voltage at 130 to 145V.  That would provide enough voltage and current headroom.  I think those devices will run nicely up to 10 meters and perhaps above.

[IN3IEX]

C2M0160120D
1200V 12A 125Wdiss.

Input Capacitance 527 pF
Output Capacitance 47pF
Reverse Transfer Capacitance 4pF

Turn-On Delay Time 7 ns
Fall Time 7ns
Turn-Off Delay Time 13ns
Rise Time 12ns

Drain-Source On-State Resistance
160 - 196mΩ

Looks better

[steve_qix]

Looking at the C2M0160120D - it's interesting looking at the curves.  A standard silicon MOSFET is quite a bit more rugged if you check out the SOA curves than these new devices.  The new devices look as if they will switch quite a bit faster within the limits of the gate resistance (nice that it's specified).  If the gate resistance were lower, it might be possible to drive these successfully at 30mHz although it still might work up there if the gate structure can withstand the power dissipated within the gate resistance itself.

Interesting!