tiny GaN fets

To be fair, for their intended application there's a premium on sub-nanohenry inductances. I reverse-engineered the drive circuit of a long-range vehicular lidar a few years back--it had one of those FETs dumping a few-nanofarad capacitor charged to ~40V into a triple-stacked diode laser, producing a pulse of several amps, about 5 ns wide.

I measured the waveforms and made an LTspice model that matched extremely well--200 pH in the drain and 180 pH in the source, for a total of less than 400 pH for the entire circuit. (And all at pH 7. ) ;)

Cheers

Phil Hobbs

Am 02.06.21 um 17:49 schrieb snipped-for-privacy@highlandsniptechnology.com:

I did solder them in with just a little bit of hot air. Very little, or you won't find them again.

It was surprisingly easy.

< Gerhard

onsdag den 2. juni 2021 kl. 19.15.02 UTC+2 skrev Gerhard Hoffmann:

or maybe a hot plate?

You might get a pcb, or part of one, an make some size converters similar to the surface mount to dip in concept. Considering the numbers Phill mentioned, you'd probably need to exercise care. A nice group of .25 by .375 inch pcbs with the fets mounted and ready to be diced and soldered edgewise up to larger boards.

Hul

snipped-for-privacy@highlandsniptechnology.com wrote:

We did make some adapter boards, to experiment with the parts.

EPC's Spice models are pretty good, which helps avoid breadboarding and iteration. EPC is adamant about never packaging these parts, or supplying adapters for testing.

I've done a few mouse-bite baby boards with the EPC parts and drivers and such, as throw-aways in case we blow one up.

These parts are very fragile. A mild touch can fracture a corner, or break the fet off the board and leave its balls behind. So it's best to glob-top them, and then they are impossible to rework.

John - you sound well ahead of what I suggested. Those tiny packages are truelly approaching die size devices.

Hul

snipped-for-privacy@highlandsniptechnology.com wrote:

Mechanically, they are horrendous. But electrically, they are magical, and replace bipolars and mesfets and phemts that are EOL now.

Cheap, too.

Here's a 25 volt pulse into 50 ohms, from a 50 volt supply, a totem pole of two of the tiny 4-ball parts.

Dr Fauci says to wear a mask so you don't blow them away with your breath.

What did that poor FET ever do to you?

I don't abuse innocent baby ganfets. That's just the way it came, next to an 0603 resistor for scale.