On Tue, 26 May 2026 22:34:22 -0000 (UTC), Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
John Larkin <jl@htigct.com> wrote:
On Tue, 26 May 2026 11:28:58 -0000 (UTC), Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
Jeroen Belleman <jeroen@nospam.please> wrote:
On 5/26/26 01:44, Phil Hobbs wrote:
Jeroen Belleman <jeroen@nospam.please> wrote:
On 5/25/26 23:27, Phil Hobbs wrote:
Jeroen Belleman <jeroen@nospam.please> wrote:
On 5/25/26 17:45, Phil Hobbs wrote:
John Larkin <jl@htigct.com> wrote:
On Sun, 24 May 2026 17:04:56 -0700, John Larkin <jl@htigct.com> wrote:
On Sun, 24 May 2026 22:55:29 -0000 (UTC), Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
John Larkin <jl@htigct.com> wrote:I did breakouts for them, and some other EPC parts.
On Sun, 24 May 2026 14:40:07 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
On 2026-05-21 13:59, john larkin wrote:
On Wed, 20 May 2026 22:38:11 +0100, JM
<sunaecoNoChoppedPork@gmail.com> wrote:
Squeaky D. talks to Alex Lidow of EPC
https://www.youtube.com/watch?v=PhGLJhfbdSk
The EPC parts are great. They claimed that they would never make
packaged (non-BGA) parts, but they are now.
GaN ICs will be very cool.
Dunno. There are no P-channel GaN FETs, because the hole mobility in
III-V systems is the pits--much worse than in silicon. That's why, as
they used to say, "GaAs is the material of the future, and always will
be." ;)
IIRC somebody posted some months back about a new material that had
really amazing hole mobility.
Cheers
Phil Hobbs
Yes, something like a p-channel GaN fet would be wonderful. I'm making
half bridges with GaN fets and the high side driver is a true pain.
There are integrated drivers but they are all slow. >>>>>>>>>>>>>>
Simon is getting a bunch of EPC2037 and 2038 breakout boards made. I want
to try them out as front ends and class-H series pass devices. >>>>>>>>>>>>
I found the 2037 and 2038 to be very fragile. Touch them, and they may
shatter or just jump off the board. I put them on a little mouse-bite
pcb; we test them and then glop the GaN fets. If a fet fails, we can
replace the entire little board.
Even the glopping is tricky.
https://www.dropbox.com/scl/fi/63n46k3ajlz02yzv6nzcn/T577s_P500D.jpg?rlkey=98osx44410u4rbqwea0jbzlj6&raw=1
They?re super high-g_M pHEMTs with interelectrode capacitances similar to a
CPH3910 and very low gate resistance.
Wonderful parts.
The noise of an ideal FET is
e_N = sqrt ((4kT/e)*2/(3 g_M)),
i.e. a bit below the Johnson noise of 1/g_M.
Since g_M is huge, and the actual gate resistance is less than an ohm, the
total is only a bit more than an ohm.
So maybe they?re down in the 150 pV range. Or maybe not. >>>>>>>>>>>>>
Cheers
Phil Hobbs
https://www.dropbox.com/scl/fi/89yua1fcvobcif6u33qaa/EPC_Breakouts.JPG?rlkey=osw22otjne7r5lqpcs463ku2z&raw=1
https://www.dropbox.com/scl/fi/i8osizmo1zxrfevpzxwqo/GaN_Boards.JPG?rlkey=2pnzr1cvrg4fj0f0yq1euvmdq&raw=1
Similar but smaller?0.3 inch square, single sided, no castellated holes. I
really want them to be good in front ends!
Cheers
Phil Hobbs
4kT/e?
Jeroen Belleman
Ideally a FET?s noise is sqrt(2/3) times the calculated Johnson noise of
g_M, a bit more than a BJT, which is sqrt(1/2).
But these things are like 1A/V, and the specified gate resistance is under
an ohm, so the spherical-cow noise is about 0.15 nV in 1 Hz.
Cheers
Phil Hobbs
It's not the right dimension. It should be
E_n = sqrt (4kT*2/(3 g_M)).
Jeroen Belleman
Right. You didn?t like my way of putting it?
Cheers
Phil Hobbs
I just removed the factor 1/e, which I believe shouldn't
be there.
Jeroen Belleman
I?ve just got shot noise on the brain. ;)
Cheers
Phil o
The gate current shot noise may be the thing that wrecks the idea.
Unless you are amplifying the sig from a current shunt or something
low impedance.
Might well be. OTOH I?m expecting to work at low I_D, so maybe I?ll luck
out.
I want them for the thermal Faraday shield anyway.
Cheers
Phil Hobbs
Here is a cute circuit:
https://www.dropbox.com/scl/fi/k9w8sq2k6uorlz7ka3cq4/2N7000_Cute_1.jpg?rlkey=3nb5ingnde1rbtxu9j4uxox9t&raw=1
Touch B to G and the LED goes on.
G to gnd and it goes off.
Tap D to G and it lights half-bright. It will stay that way for days.
Easy way to test for gate leakage.
T to G is fun too.
G to
John Larkin
Highland Tech Glen Canyon Design Center
Lunatic Fringe Electronics
Here is a cute circuit:
https://www.dropbox.com/scl/fi/k9w8sq2k6uorlz7ka3cq4/2N7000_Cute_1.jpg?rlkey=3nb5ingnde1rbtxu9j4uxox9t&raw=1
Touch B to G and the LED goes on.
G to gnd and it goes off.
Tap D to G and it lights half-bright. It will stay that way for days.
Easy way to test for gate leakage.
T to G is fun too.
G to
John Larkin
Highland Tech Glen Canyon Design Center
Lunatic Fringe Electronics
[...]>
Here is a cute circuit:
https://www.dropbox.com/scl/fi/k9w8sq2k6uorlz7ka3cq4/2N7000_Cute_1.jpg?rlkey=3nb5ingnde1rbtxu9j4uxox9t&raw=1
Touch B to G and the LED goes on.
G to gnd and it goes off.
Tap D to G and it lights half-bright. It will stay that way for days.
Easy way to test for gate leakage.
T to G is fun too.
G to
John Larkin
Highland Tech Glen Canyon Design Center
Lunatic Fringe Electronics
How about this one: On/Off with the same push button. ><http://cern.ch/jeroen/tmp/onoff.gif>
Jeroen Belleman
[...]>
Here is a cute circuit:
https://www.dropbox.com/scl/fi/k9w8sq2k6uorlz7ka3cq4/2N7000_Cute_1.jpg?rlkey=3nb5ingnde1rbtxu9j4uxox9t&raw=1
Touch B to G and the LED goes on.
G to gnd and it goes off.
Tap D to G and it lights half-bright. It will stay that way for days.
Easy way to test for gate leakage.
T to G is fun too.
G to
John Larkin
Highland Tech Glen Canyon Design Center
Lunatic Fringe Electronics
How about this one: On/Off with the same push button. <http://cern.ch/jeroen/tmp/onoff.gif>
Jeroen Belleman
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