The AM Forum

       This is a one lung Xtal oscillator built with a power GaN FET
from Transphorm TPH3206PSB, I got from Digi-Key. The device runs
cool, load resistor hot.  Amazing switching speeds driven
from a FT-243 Xtal 3.881MHz no driver!  I hope these pics come
out, 13.8vdc supply.   I'm catching up reading the other work done here.
Schematic, scope 10ns/div H, 5v/div V.   then 100ns/div

Dean

Excellent Dean, great to see experiments on the leading edge of technology.  Your oscillator just scratches the surface of what that GaN FET is capable of.  They really shine at 40M and above thanks to their fast speed. A 20M GaN AM transmitter in the 250 to 300 Watt range is definitely on my bucket list. Keep up the good work and take it to the next level.
73s  Nigel

Hi Nigel
       In the 80's I got a power Mosfet class D xmtr going at about 100watts. The devices were slow, huge
gate C, large Rds, it needed many devices.   It was pwm'd worked pretty well.  Nothing like this GaN FET!   I'm looking
at the TransPhorm PQFN88 flat package. App notes indicate it has lower inductance, less parasitics.   but it looks
like its designed for reflow pcb soldering.  is there like a bed of nails socket for this? curious

73 dean

Yea Ive looked at those paks also and the EPC line which use solder bumps.  While the specs look great I cant think how to mount them using simple homemade hobby grade SMT PCBs.  I'm certainly not equipped for flow soldering and not aware of any sockets.  A major step forward by Transphorm is the common source TO220 TO247 package which really make life easier. Wish all FETs were made that way.

73s  Nigel

You need a heat plate.

Could put them down with an SMT 'Hairdryer' at a pinch.

J.