J
Joe Gwinn
Guest
On Thu, 3 Mar 2022 17:43:15 -0500, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
I\'ve worked with a IC foundry for Gallium based analog RF components,
and they do have full-accuracy models, which are closely held as trade
secrets. I also recall comments by various SED denizens to the same
effect.
Yes. The foundry design modeling systems are often bespoke, for
precisely those reasons.
As others have said, harmonic-balance simulators are widely used as
well.
Many use RF design systems from such as HP/Agilent. Some use COMSOL.
Yes, these are excuses. But the problem is not technical.
Joe Gwinn
<pcdhSpamMeSenseless@electrooptical.net> wrote:
Joe Gwinn wrote:
On Thu, 03 Mar 2022 13:13:01 -0800, John Larkin
jlarkin@highland_atwork_technology.com> wrote:
On Thu, 03 Mar 2022 15:52:13 -0500, Joe Gwinn <joegwinn@comcast.net
wrote:
On Thu, 3 Mar 2022 12:20:12 -0500, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:
jlarkin@highlandsniptechnology.com wrote:
On Thu, 3 Mar 2022 17:10:41 +0000, Tom Gardner
spamjunk@blueyonder.co.uk> wrote:
On 03/03/22 16:25, jlarkin@highlandsniptechnology.com wrote:
On Thu, 3 Mar 2022 11:12:30 -0500, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:
jlarkin@highlandsniptechnology.com wrote:
On Thu, 3 Mar 2022 06:32:58 +0100, Gerhard Hoffmann <dk4xp@arcor.de
wrote:
Am 03.03.22 um 05:54 schrieb jlarkin@highlandsniptechnology.com:
On Wed, 2 Mar 2022 20:27:20 -0800 (PST), Rich S
richsulinengineer@gmail.com> wrote:
Those loadpull charts on page 5 are a mess,
unreadable, If this is what its like, then
No wonder a lot of RF guys retire unexpectedly.
RF lives in the dark ages. We need Spice models.
Don\'t mke me laugh so hard. Spice IS the dark ages.
What we need is AWR or ADS design kits.
Gerhard
What\'s wrong with knowing all the voltages and currents as a function
of time?
If you know that, you know all the RF stuff. That doesn\'t work in
reverse.
And what\'s wrong with knowing drain current as a function of gate
voltage? RF data sheets usually say \"turn the trimpot until the RF
comes out.\"
I wonder how people generate those \"design kits\" if they don\'t know
the basic electrical properties of the part. Maybe it\'s like \"load
pull\" engineering.
They probably make about eight of them over the lifetime of the part, so
statistics are hard to come by.
Cheers
Phil Hobbs
Rf is a strange world. I think its traditions pre-date computers, so
they emphasize analytical, necessarily linear, ideas like s-params and
Smith charts. Things that could be sort-of handled with pencils and
slide rules.
Yes. Well before computers. And the key was finding the right
mathematical and physical approximations, yielding an analytically
tractable theory that was also useful.
That\'s because non-linearities are avoided like the plague.
They cause harmonics that screw you /and other/ users up.
So wouldn\'t you want a Spice model to evaluate that? Not all parts are
used small-signal.
Well, the device manufacturers do have such models, but the
manufacturers do not release anything that revealing, to avoid
educating their competitors.
A few competitors will spend big bucks to measure the enemies parts,
and they have the facilities to do it. So why should a thousand
end-users have to do the measurements themselves, or spin product revs
until it works?
I asked MiniCircuits for Spice models of their phemts. They were
adamant, agressive even, that they will NEVER have Spice models.
Yes, but they *do* have them.
You know this how, exactly?
I\'ve worked with a IC foundry for Gallium based analog RF components,
and they do have full-accuracy models, which are closely held as trade
secrets. I also recall comments by various SED denizens to the same
effect.
Yes. The foundry design modeling systems are often bespoke, for
precisely those reasons.
As others have said, harmonic-balance simulators are widely used as
well.
Many use RF design systems from such as HP/Agilent. Some use COMSOL.
Yes, these are excuses. But the problem is not technical.
Joe Gwinn