Homebrew PCBs

It sounds like an interesting project.

The 3D drawing would be helpful so would be some links to the manufacturer.

What is so special about the current package that makes it so expensive.

Any references on the refrigeration process?

So many questions..

Good Luck,

Bertho

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From: shoestring   Sent: Tuesday, August 02, 2011 13:36
Hello HPCBers,

I've this special project that requires some innovation to be practical 
on my budget.

The gallium nitride transistor is new, invented by a grad student in 
2006, and used by the military. The cost of packages that exploit the 
ultra-fast dV/dt (4 volts per nanosecond) is upwards of $200 each. I've 
seen as high as seven-hundred dollars for a GaN in a high-current package.

Good news... the raw die, with solder-bumps for reflow-soldering, is 
available for around $5 each (five bucks).

However, standard circuit board surface mounts will not celebrate the 
GaN transistor's chiefest qualities --speed. My personal project (as a 
retired programmer), a resonant refrigerator, depends on short, high 
power pulses beyond what a MOSFET can do... enter the GaN transistor.

I've a design that is innovative, I reckon. It involves producing the 
0.025 millimeter circuit-board landing pads for reflow soldering by 
stacking copper foil of the same thickness, with the insulation path 
between pads filled with epoxy. The completed lamination is sawn into 
small strips and polished, and the laminations on the edge become the 
landing pads for the GaNs.

I've 3D perspective illustrations if anyone is interested. What I'm 
hoping to find is an EE perspective of the necessary things, like solder 
masking the tiny buss, and things I'm unfamiliar with. I am proceeding 
slowly, shoestring budget in force.

Testing is also needed, and I'm learning the details of RF as I go... 
all advise is special.

Thanks,
AZdon



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