gallium nitride (gan) fet

[dbanner]

Can Ganfets be used for coil switch in PI tx circuit? They're supposed to be more efficient than typical Mosfet. But are the other electrical properties suitable for such an application?
Has anyone experimented with these devices?
I haven't studied any datasheet on these devices, just thought I'd ask the question.

[Carl-NC]

I've never tried one. It appears as if it will work just fine, but I'm not sure if it will be beneficial. The one device I looked at had worse Ciss and Coss than an IRF840. RDSon is way better but rarely is that a limiting issue in a PI due to the coil R. Also, I noticed drain & source pins are swapped on the TO220 package so beware trying to do a direct swap.

[dbanner]

They are supposed to have faster on/off times because of significantly lower gate charge, and also mentioned is lower output capacitance.
I also read about the absence of the traditional body diode.
Perhaps it is worth exploring. The pinout difference you mentioned is a sure trap.

[Carl-NC]

I also read about the absence of the traditional body diode.

Hmmm, that might be interesting.

[6666]

Just did a random search data sheet showed diode, but the symbol also shows some sort of parallel fet between D and S, weird .

[Qiaozhi]

From a Texas Instruments GaN datasheet:

"Unlike silicon MOSFETs, there is no p-n junction from source to drain in GaN devices. That is why GaN devices have no reverse recovery losses. However, the GaN device can still conduct from source to drain in 3rd quadrant of operation similar to a body diode but with higher voltage drop and higher conduction loss. 3rd quadrant operation can be defined as follows; when the GaN device is turned off and negative current pulls the drain node voltage to be lower than its source.The voltage drop across GaN device during 3rd quadrant operation is high; therefore, it is recommended to operate with synchronous switching and keep the duration of 3rd quadrant operation at minimum."

[Skippy]

Yes, no actual body diode, but they still conduct as though they had one.
I was unaware of this until that PI project posted here last year, where the fellow blew up a FET driver IC by turning on the body diodes hard. I wondered if there were any oddball FET devices that genuinely had no diode, such as silicon-on-sapphire types. My search led me to this article that deals with GaN devices:

https://gansystems.com/newsroom/comm...et-body-diode/