Super duper hype fast FET driver?

J

Joerg

Guest
Folks,

Have to drive around a hundred pF or so in parallel with maybe a few
hundred ohms blazingly fast. 10-12V amplitude, transitions ideally
sub-nanosecond from 10-90% both directions. Not too boutiquish or
unobtanium (which excludes certain companies ...) and not more than a
few Dollars. Shouldn't introduce noise when low. Low quiescent current,
preferably under 20mA.

Looked around and the fastest one I could see is this dude:

http://www.diodes.com/datasheets/ZXGD3003E6.pdf

Not too much data but it gets into the 2nsec range. Anyone aware of a
driver with even more testosterone?

Of course the ideal scenario would be a push-pull MMIC with 15V or more
supply voltage but that ain't going to happen. Same with RF switches,
even if they could take 12V they are surprisingly slow in switch action.

Ok, could roll my own, of course. But that gets to be involved and a bit
too big for this project.

--
Regards, Joerg

http://www.analogconsultants.com/
 
On Thu, 18 Aug 2011 12:59:05 -0700, Joerg <invalid@invalid.invalid>
wrote:

Folks,

Have to drive around a hundred pF or so in parallel with maybe a few
hundred ohms blazingly fast. 10-12V amplitude, transitions ideally
sub-nanosecond from 10-90% both directions. Not too boutiquish or
unobtanium (which excludes certain companies ...) and not more than a
few Dollars. Shouldn't introduce noise when low. Low quiescent current,
preferably under 20mA.

Looked around and the fastest one I could see is this dude:

http://www.diodes.com/datasheets/ZXGD3003E6.pdf

Not too much data but it gets into the 2nsec range. Anyone aware of a
driver with even more testosterone?
Click to expand...
The rise/fall times are mediocre. A little series inductive peaking
would help.

Gate driver chips are cool, though. They have lots of off-label uses.

Of course the ideal scenario would be a push-pull MMIC with 15V or more
supply voltage but that ain't going to happen. Same with RF switches,
even if they could take 12V they are surprisingly slow in switch action.

Ok, could roll my own, of course. But that gets to be involved and a bit
too big for this project.
Click to expand...
What's the load? Need DC coupling/long pulses?

I know how to get 6 or 7 volts of brutal sub-ns swing cheap, at zero
Iq. Could be doubled, depending. Not for public release.

John
 
John Larkin wrote:
On Thu, 18 Aug 2011 12:59:05 -0700, Joerg <invalid@invalid.invalid
wrote:

Folks,

Have to drive around a hundred pF or so in parallel with maybe a few
hundred ohms blazingly fast. 10-12V amplitude, transitions ideally
sub-nanosecond from 10-90% both directions. Not too boutiquish or
unobtanium (which excludes certain companies ...) and not more than a
few Dollars. Shouldn't introduce noise when low. Low quiescent current,
preferably under 20mA.

Looked around and the fastest one I could see is this dude:

http://www.diodes.com/datasheets/ZXGD3003E6.pdf

Not too much data but it gets into the 2nsec range. Anyone aware of a
driver with even more testosterone?

The rise/fall times are mediocre. A little series inductive peaking
would help.
Click to expand...
Mediocre? At high capacitive load maybe but at low loads I think they
are amazing for a 25c part. Most others including its other ZXGD300x
brethren peter out towards 10nsec for one of both slopes towards zero
capacitance.


Gate driver chips are cool, though. They have lots of off-label uses.
Click to expand...
Oh yeah :)


Of course the ideal scenario would be a push-pull MMIC with 15V or more
supply voltage but that ain't going to happen. Same with RF switches,
even if they could take 12V they are surprisingly slow in switch action.

Ok, could roll my own, of course. But that gets to be involved and a bit
too big for this project.

What's the load? Need DC coupling/long pulses?
Click to expand...
Pulses are under 100nsec length and duty cycle is well under 5%. Getting
DC across would be great but I am afraid I'll have to clamp that ...
somehow ... because it's a high voltage I'll have to move with that. Or
I'll let this whole thing ride on the rail. Woe to dose who toucha wid
da fingahs :)


I know how to get 6 or 7 volts of brutal sub-ns swing cheap, at zero
Iq. Could be doubled, depending. Not for public release.
Click to expand...
7V would be a bit low, and I'd need zippy in both directions.

--
Regards, Joerg

http://www.analogconsultants.com/
 
"Joerg" wrote in message news:9b598jFfh1U1@mid.individual.net...

Folks,

Have to drive around a hundred pF or so in parallel with maybe a few
hundred ohms blazingly fast. 10-12V amplitude, transitions ideally
sub-nanosecond from 10-90% both directions. Not too boutiquish or
unobtanium (which excludes certain companies ...) and not more than a
few Dollars. Shouldn't introduce noise when low. Low quiescent current,
preferably under 20mA.

Looked around and the fastest one I could see is this dude:

http://www.diodes.com/datasheets/ZXGD3003E6.pdf

Not too much data but it gets into the 2nsec range. Anyone aware of a
driver with even more testosterone?

Of course the ideal scenario would be a push-pull MMIC with 15V or more
supply voltage but that ain't going to happen. Same with RF switches,
even if they could take 12V they are surprisingly slow in switch action.

Ok, could roll my own, of course. But that gets to be involved and a bit
too big for this project.

------------

Have you thought about precharging the gates? Does the fets need to turn of
completely to be effective?
 
On Thu, 18 Aug 2011 14:01:41 -0700, Joerg <invalid@invalid.invalid>
wrote:

John Larkin wrote:
On Thu, 18 Aug 2011 12:59:05 -0700, Joerg <invalid@invalid.invalid
wrote:

Folks,

Have to drive around a hundred pF or so in parallel with maybe a few
hundred ohms blazingly fast. 10-12V amplitude, transitions ideally
sub-nanosecond from 10-90% both directions. Not too boutiquish or
unobtanium (which excludes certain companies ...) and not more than a
few Dollars. Shouldn't introduce noise when low. Low quiescent current,
preferably under 20mA.

Looked around and the fastest one I could see is this dude:

http://www.diodes.com/datasheets/ZXGD3003E6.pdf

Not too much data but it gets into the 2nsec range. Anyone aware of a
driver with even more testosterone?

The rise/fall times are mediocre. A little series inductive peaking
would help.


Mediocre? At high capacitive load maybe but at low loads I think they
are amazing for a 25c part. Most others including its other ZXGD300x
brethren peter out towards 10nsec for one of both slopes towards zero
capacitance.


Gate driver chips are cool, though. They have lots of off-label uses.


Oh yeah :)


Of course the ideal scenario would be a push-pull MMIC with 15V or more
supply voltage but that ain't going to happen. Same with RF switches,
even if they could take 12V they are surprisingly slow in switch action.

Ok, could roll my own, of course. But that gets to be involved and a bit
too big for this project.

What's the load? Need DC coupling/long pulses?


Pulses are under 100nsec length and duty cycle is well under 5%. Getting
DC across would be great but I am afraid I'll have to clamp that ...
somehow ... because it's a high voltage I'll have to move with that. Or
I'll let this whole thing ride on the rail. Woe to dose who toucha wid
da fingahs :)


I know how to get 6 or 7 volts of brutal sub-ns swing cheap, at zero
Iq. Could be doubled, depending. Not for public release.


7V would be a bit low, and I'd need zippy in both directions.
Click to expand...
If you need high-side drive, a pair of my drivers could feed opposite
ends of a 1:1 transmission line transformer (or maybe a balun) to
double the swing. 12 volts for 100 ns would be no problem, edges well
below a ns.

At below 5% duty cycle, you probably don't need to DC restore.

It'll cost you a burger and a couple of beers. Zeitgeist has about 40
on tap.

If pulse width is fixed, there's another way to do it: a really fast
open-drain mosfet feeding a 1:1 transformer, 12 volts or whatever you
like. The magnetizing current powers the falling edge. Also cheap.

John
 
On Thu, 18 Aug 2011 17:00:10 -0500, "DonMack" <DonMack@Maill.com>
wrote:

"Joerg" wrote in message news:9b598jFfh1U1@mid.individual.net...

Folks,

Have to drive around a hundred pF or so in parallel with maybe a few
hundred ohms blazingly fast. 10-12V amplitude, transitions ideally
sub-nanosecond from 10-90% both directions. Not too boutiquish or
unobtanium (which excludes certain companies ...) and not more than a
few Dollars. Shouldn't introduce noise when low. Low quiescent current,
preferably under 20mA.

Looked around and the fastest one I could see is this dude:

http://www.diodes.com/datasheets/ZXGD3003E6.pdf

Not too much data but it gets into the 2nsec range. Anyone aware of a
driver with even more testosterone?

Of course the ideal scenario would be a push-pull MMIC with 15V or more
supply voltage but that ain't going to happen. Same with RF switches,
even if they could take 12V they are surprisingly slow in switch action.

Ok, could roll my own, of course. But that gets to be involved and a bit
too big for this project.

------------

Have you thought about precharging the gates? Does the fets need to turn of
completely to be effective?
Click to expand...
I've done that, biased a gate just below threshold, to optimize a
driver that had limited swing. The total gate charge doesn't change
much, but sometimes a couple of volts of additional enhancement can
help a lot.

John
 
On 19 elo, 00:01, Joerg <inva...@invalid.invalid> wrote:
John Larkin wrote:
On Thu, 18 Aug 2011 12:59:05 -0700, Joerg <inva...@invalid.invalid
wrote:

Folks,

Have to drive around a hundred pF or so in parallel with maybe a few
hundred ohms blazingly fast. 10-12V amplitude, transitions ideally
sub-nanosecond from 10-90% both directions. Not too boutiquish or
unobtanium (which excludes certain companies ...) and not more than a
few Dollars. Shouldn't introduce noise when low. Low quiescent current,
preferably under 20mA.

Looked around and the fastest one I could see is this dude:

http://www.diodes.com/datasheets/ZXGD3003E6.pdf

Not too much data but it gets into the 2nsec range. Anyone aware of a
driver with even more testosterone?

The rise/fall times are mediocre. A little series inductive peaking
would help.

Mediocre? At high capacitive load maybe but at low loads I think they
are amazing for a 25c part. Most others including its other ZXGD300x
brethren peter out towards 10nsec for one of both slopes towards zero
capacitance.

Gate driver chips are cool, though. They have lots of off-label uses.

Oh yeah :)

Of course the ideal scenario would be a push-pull MMIC with 15V or more
supply voltage but that ain't going to happen. Same with RF switches,
even if they could take 12V they are surprisingly slow in switch action.

Ok, could roll my own, of course. But that gets to be involved and a bit
too big for this project.

What's the load? Need DC coupling/long pulses?

Pulses are under 100nsec length and duty cycle is well under 5%. Getting
DC across would be great but I am afraid I'll have to clamp that ...
somehow ... because it's a high voltage I'll have to move with that. Or
I'll let this whole thing ride on the rail. Woe to dose who toucha wid
da fingahs :)

I know how to get 6 or 7 volts of brutal sub-ns swing cheap, at zero
Iq. Could be doubled, depending. Not for public release.

7V would be a bit low, and I'd need zippy in both directions.

--
Regards, Joerg

http://www.analogconsultants.com/
Click to expand...
Are Zetex parts OK nowadays. I now a biggish business who wont take
those because of reliability problems. The case was too small for the
chip inside, or something like that, I was told.
 
John Larkin wrote:
On Thu, 18 Aug 2011 14:01:41 -0700, Joerg <invalid@invalid.invalid
wrote:

John Larkin wrote:
On Thu, 18 Aug 2011 12:59:05 -0700, Joerg <invalid@invalid.invalid
wrote:

Folks,

Have to drive around a hundred pF or so in parallel with maybe a few
hundred ohms blazingly fast. 10-12V amplitude, transitions ideally
sub-nanosecond from 10-90% both directions. Not too boutiquish or
unobtanium (which excludes certain companies ...) and not more than a
few Dollars. Shouldn't introduce noise when low. Low quiescent current,
preferably under 20mA.

Looked around and the fastest one I could see is this dude:

http://www.diodes.com/datasheets/ZXGD3003E6.pdf

Not too much data but it gets into the 2nsec range. Anyone aware of a
driver with even more testosterone?
The rise/fall times are mediocre. A little series inductive peaking
would help.

Mediocre? At high capacitive load maybe but at low loads I think they
are amazing for a 25c part. Most others including its other ZXGD300x
brethren peter out towards 10nsec for one of both slopes towards zero
capacitance.


Gate driver chips are cool, though. They have lots of off-label uses.

Oh yeah :)


Of course the ideal scenario would be a push-pull MMIC with 15V or more
supply voltage but that ain't going to happen. Same with RF switches,
even if they could take 12V they are surprisingly slow in switch action.

Ok, could roll my own, of course. But that gets to be involved and a bit
too big for this project.
What's the load? Need DC coupling/long pulses?

Pulses are under 100nsec length and duty cycle is well under 5%. Getting
DC across would be great but I am afraid I'll have to clamp that ...
somehow ... because it's a high voltage I'll have to move with that. Or
I'll let this whole thing ride on the rail. Woe to dose who toucha wid
da fingahs :)


I know how to get 6 or 7 volts of brutal sub-ns swing cheap, at zero
Iq. Could be doubled, depending. Not for public release.

7V would be a bit low, and I'd need zippy in both directions.

If you need high-side drive, a pair of my drivers could feed opposite
ends of a 1:1 transmission line transformer (or maybe a balun) to
double the swing. 12 volts for 100 ns would be no problem, edges well
below a ns.
Click to expand...
RF parts such as baluns or obscure directional couplers with a voodoo
coefficient never scared me.


At below 5% duty cycle, you probably don't need to DC restore.
Click to expand...
Not sure yet if I do. This high voltages acts as kind of a reference
somewhere. It's one of those circuits that most people won't even touch
with a 10ft pole.


It'll cost you a burger and a couple of beers. Zeitgeist has about 40
on tap.
Click to expand...
I am game. But I have no idea when I get to S.F. the next time. A lot of
my clients are no longer in California, for reasons we all know, and
Villaraigosa has just made that loud and clear to companies once more :-(

Now if you ever get into this area we have a very nice Japanese
restaurant. Blue Moon and Sapporo on tap.


If pulse width is fixed, there's another way to do it: a really fast
open-drain mosfet feeding a 1:1 transformer, 12 volts or whatever you
like. The magnetizing current powers the falling edge. Also cheap.
Click to expand...
It must remain adjustable.

--
Regards, Joerg

http://www.analogconsultants.com/
 
DonMack wrote:
"Joerg" wrote in message news:9b598jFfh1U1@mid.individual.net...

Folks,

Have to drive around a hundred pF or so in parallel with maybe a few
hundred ohms blazingly fast. 10-12V amplitude, transitions ideally
sub-nanosecond from 10-90% both directions. Not too boutiquish or
unobtanium (which excludes certain companies ...) and not more than a
few Dollars. Shouldn't introduce noise when low. Low quiescent current,
preferably under 20mA.

Looked around and the fastest one I could see is this dude:

http://www.diodes.com/datasheets/ZXGD3003E6.pdf

Not too much data but it gets into the 2nsec range. Anyone aware of a
driver with even more testosterone?

Of course the ideal scenario would be a push-pull MMIC with 15V or more
supply voltage but that ain't going to happen. Same with RF switches,
even if they could take 12V they are surprisingly slow in switch action.

Ok, could roll my own, of course. But that gets to be involved and a bit
too big for this project.

------------

Have you thought about precharging the gates? Does the fets need to turn
of completely to be effective?
Click to expand...

This isn't a gate but another capacitive load. The goal is to make the
pulse waveform look as perfectly square as can be.

Wish I could find something like the NE3509 that can take 15-20V instead
of just 4V.

--
Regards, Joerg

http://www.analogconsultants.com/
 
On Thu, 18 Aug 2011 18:06:13 -0700, Joerg <invalid@invalid.invalid> wrote:

John Larkin wrote:
On Thu, 18 Aug 2011 14:01:41 -0700, Joerg <invalid@invalid.invalid
wrote:

John Larkin wrote:
On Thu, 18 Aug 2011 12:59:05 -0700, Joerg <invalid@invalid.invalid
wrote:

Folks,

Have to drive around a hundred pF or so in parallel with maybe a few
hundred ohms blazingly fast. 10-12V amplitude, transitions ideally
sub-nanosecond from 10-90% both directions. Not too boutiquish or
unobtanium (which excludes certain companies ...) and not more than a
few Dollars. Shouldn't introduce noise when low. Low quiescent current,
preferably under 20mA.

Looked around and the fastest one I could see is this dude:

http://www.diodes.com/datasheets/ZXGD3003E6.pdf

Not too much data but it gets into the 2nsec range. Anyone aware of a
driver with even more testosterone?
The rise/fall times are mediocre. A little series inductive peaking
would help.

Mediocre? At high capacitive load maybe but at low loads I think they
are amazing for a 25c part. Most others including its other ZXGD300x
brethren peter out towards 10nsec for one of both slopes towards zero
capacitance.


Gate driver chips are cool, though. They have lots of off-label uses.

Oh yeah :)


Of course the ideal scenario would be a push-pull MMIC with 15V or more
supply voltage but that ain't going to happen. Same with RF switches,
even if they could take 12V they are surprisingly slow in switch action.

Ok, could roll my own, of course. But that gets to be involved and a bit
too big for this project.
What's the load? Need DC coupling/long pulses?

Pulses are under 100nsec length and duty cycle is well under 5%. Getting
DC across would be great but I am afraid I'll have to clamp that ...
somehow ... because it's a high voltage I'll have to move with that. Or
I'll let this whole thing ride on the rail. Woe to dose who toucha wid
da fingahs :)


I know how to get 6 or 7 volts of brutal sub-ns swing cheap, at zero
Iq. Could be doubled, depending. Not for public release.

7V would be a bit low, and I'd need zippy in both directions.

If you need high-side drive, a pair of my drivers could feed opposite
ends of a 1:1 transmission line transformer (or maybe a balun) to
double the swing. 12 volts for 100 ns would be no problem, edges well
below a ns.


RF parts such as baluns or obscure directional couplers with a voodoo
coefficient never scared me.


At below 5% duty cycle, you probably don't need to DC restore.


Not sure yet if I do. This high voltages acts as kind of a reference
somewhere. It's one of those circuits that most people won't even touch
with a 10ft pole.


It'll cost you a burger and a couple of beers. Zeitgeist has about 40
on tap.


I am game. But I have no idea when I get to S.F. the next time. A lot of
my clients are no longer in California, for reasons we all know, and
Villaraigosa has just made that loud and clear to companies once more :-(

Now if you ever get into this area we have a very nice Japanese
restaurant. Blue Moon and Sapporo on tap.


If pulse width is fixed, there's another way to do it: a really fast
open-drain mosfet feeding a 1:1 transformer, 12 volts or whatever you
like. The magnetizing current powers the falling edge. Also cheap.


It must remain adjustable.
Click to expand...
Never turn down an offer from Larkin. He's promised you a half-fast solution,
and I'm sure he can deliver ;-)

...Jim Thompson

[On the Road, in New York]
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
On Thu, 18 Aug 2011 21:18:40 -0400, Jim Thompson
<To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

On Thu, 18 Aug 2011 18:06:13 -0700, Joerg <invalid@invalid.invalid> wrote:

John Larkin wrote:
On Thu, 18 Aug 2011 14:01:41 -0700, Joerg <invalid@invalid.invalid
wrote:

John Larkin wrote:
On Thu, 18 Aug 2011 12:59:05 -0700, Joerg <invalid@invalid.invalid
wrote:

Folks,

Have to drive around a hundred pF or so in parallel with maybe a few
hundred ohms blazingly fast. 10-12V amplitude, transitions ideally
sub-nanosecond from 10-90% both directions. Not too boutiquish or
unobtanium (which excludes certain companies ...) and not more than a
few Dollars. Shouldn't introduce noise when low. Low quiescent current,
preferably under 20mA.

Looked around and the fastest one I could see is this dude:

http://www.diodes.com/datasheets/ZXGD3003E6.pdf

Not too much data but it gets into the 2nsec range. Anyone aware of a
driver with even more testosterone?
The rise/fall times are mediocre. A little series inductive peaking
would help.

Mediocre? At high capacitive load maybe but at low loads I think they
are amazing for a 25c part. Most others including its other ZXGD300x
brethren peter out towards 10nsec for one of both slopes towards zero
capacitance.


Gate driver chips are cool, though. They have lots of off-label uses.

Oh yeah :)


Of course the ideal scenario would be a push-pull MMIC with 15V or more
supply voltage but that ain't going to happen. Same with RF switches,
even if they could take 12V they are surprisingly slow in switch action.

Ok, could roll my own, of course. But that gets to be involved and a bit
too big for this project.
What's the load? Need DC coupling/long pulses?

Pulses are under 100nsec length and duty cycle is well under 5%. Getting
DC across would be great but I am afraid I'll have to clamp that ...
somehow ... because it's a high voltage I'll have to move with that. Or
I'll let this whole thing ride on the rail. Woe to dose who toucha wid
da fingahs :)


I know how to get 6 or 7 volts of brutal sub-ns swing cheap, at zero
Iq. Could be doubled, depending. Not for public release.

7V would be a bit low, and I'd need zippy in both directions.

If you need high-side drive, a pair of my drivers could feed opposite
ends of a 1:1 transmission line transformer (or maybe a balun) to
double the swing. 12 volts for 100 ns would be no problem, edges well
below a ns.


RF parts such as baluns or obscure directional couplers with a voodoo
coefficient never scared me.


At below 5% duty cycle, you probably don't need to DC restore.


Not sure yet if I do. This high voltages acts as kind of a reference
somewhere. It's one of those circuits that most people won't even touch
with a 10ft pole.


It'll cost you a burger and a couple of beers. Zeitgeist has about 40
on tap.


I am game. But I have no idea when I get to S.F. the next time. A lot of
my clients are no longer in California, for reasons we all know, and
Villaraigosa has just made that loud and clear to companies once more :-(

Now if you ever get into this area we have a very nice Japanese
restaurant. Blue Moon and Sapporo on tap.


If pulse width is fixed, there's another way to do it: a really fast
open-drain mosfet feeding a 1:1 transformer, 12 volts or whatever you
like. The magnetizing current powers the falling edge. Also cheap.


It must remain adjustable.

Never turn down an offer from Larkin. He's promised you a half-fast solution,
and I'm sure he can deliver ;-)

...Jim Thompson

[On the Road, in New York]
Click to expand...


How's this?

http://www.highlandtechnology.com/DSS/T760DS.shtml

ftp://jjlarkin.lmi.net/T760_pulses.jpg

Transformer isolated 100 volt pulses into 50 ohms with rise and fall
below 1 ns. That's over 1e11 volts per second. Got any idea how to do
this?


John
 
On Thu, 18 Aug 2011 18:10:56 -0700, Joerg <invalid@invalid.invalid>
wrote:

DonMack wrote:


"Joerg" wrote in message news:9b598jFfh1U1@mid.individual.net...

Folks,

Have to drive around a hundred pF or so in parallel with maybe a few
hundred ohms blazingly fast. 10-12V amplitude, transitions ideally
sub-nanosecond from 10-90% both directions. Not too boutiquish or
unobtanium (which excludes certain companies ...) and not more than a
few Dollars. Shouldn't introduce noise when low. Low quiescent current,
preferably under 20mA.

Looked around and the fastest one I could see is this dude:

http://www.diodes.com/datasheets/ZXGD3003E6.pdf

Not too much data but it gets into the 2nsec range. Anyone aware of a
driver with even more testosterone?

Of course the ideal scenario would be a push-pull MMIC with 15V or more
supply voltage but that ain't going to happen. Same with RF switches,
even if they could take 12V they are surprisingly slow in switch action.

Ok, could roll my own, of course. But that gets to be involved and a bit
too big for this project.

------------

Have you thought about precharging the gates? Does the fets need to turn
of completely to be effective?


This isn't a gate but another capacitive load. The goal is to make the
pulse waveform look as perfectly square as can be.

Wish I could find something like the NE3509 that can take 15-20V instead
of just 4V.
Click to expand...
They are actually happy to run around 8 volts. Lovely part. But heck,
a 2N7002 can switch 15 or 20 volts in under a ns... if you bang the
gate hard enough.

Some of the mesfets can be run at 12 or even 15 volts. But the bees
knees these days is GaN fets, which work in the 40-200 volt range,
need tiny gate drives, and switch insanely fast. But not cheap.

We blew up about a kilobuck worth of Nitronex fets one afternoon. They
claim they have the process down now.

John
 
John Larkin wrote:
On Thu, 18 Aug 2011 18:10:56 -0700, Joerg <invalid@invalid.invalid
wrote:

DonMack wrote:

"Joerg" wrote in message news:9b598jFfh1U1@mid.individual.net...

Folks,

Have to drive around a hundred pF or so in parallel with maybe a few
hundred ohms blazingly fast. 10-12V amplitude, transitions ideally
sub-nanosecond from 10-90% both directions. Not too boutiquish or
unobtanium (which excludes certain companies ...) and not more than a
few Dollars. Shouldn't introduce noise when low. Low quiescent current,
preferably under 20mA.

Looked around and the fastest one I could see is this dude:

http://www.diodes.com/datasheets/ZXGD3003E6.pdf

Not too much data but it gets into the 2nsec range. Anyone aware of a
driver with even more testosterone?

Of course the ideal scenario would be a push-pull MMIC with 15V or more
supply voltage but that ain't going to happen. Same with RF switches,
even if they could take 12V they are surprisingly slow in switch action.

Ok, could roll my own, of course. But that gets to be involved and a bit
too big for this project.

------------

Have you thought about precharging the gates? Does the fets need to turn
of completely to be effective?

This isn't a gate but another capacitive load. The goal is to make the
pulse waveform look as perfectly square as can be.

Wish I could find something like the NE3509 that can take 15-20V instead
of just 4V.

They are actually happy to run around 8 volts. Lovely part. But heck,
a 2N7002 can switch 15 or 20 volts in under a ns... if you bang the
gate hard enough.
Click to expand...
The 2N7002 or BSS123 plus some magnetics would be kind of my last resort
if none of the ICs can do that. And it looks like none can. No market I
guess.


Some of the mesfets can be run at 12 or even 15 volts. But the bees
knees these days is GaN fets, which work in the 40-200 volt range,
need tiny gate drives, and switch insanely fast. But not cheap.
Click to expand...
Doesn't have to be cheap, but my definition of expensive is everything
north of $5 :)

I'll have to see what CEL has to offer. Paralleling European dual-gates
for UHF tuners might also work but that gets old.


We blew up about a kilobuck worth of Nitronex fets one afternoon. They
claim they have the process down now.
Click to expand...
Ouch!

--
Regards, Joerg

http://www.analogconsultants.com/
 
Jim Thompson wrote:
On Thu, 18 Aug 2011 18:06:13 -0700, Joerg <invalid@invalid.invalid> wrote:

John Larkin wrote:
On Thu, 18 Aug 2011 14:01:41 -0700, Joerg <invalid@invalid.invalid
wrote:

John Larkin wrote:
On Thu, 18 Aug 2011 12:59:05 -0700, Joerg <invalid@invalid.invalid
wrote:

Folks,

Have to drive around a hundred pF or so in parallel with maybe a few
hundred ohms blazingly fast. 10-12V amplitude, transitions ideally
sub-nanosecond from 10-90% both directions. Not too boutiquish or
unobtanium (which excludes certain companies ...) and not more than a
few Dollars. Shouldn't introduce noise when low. Low quiescent current,
preferably under 20mA.

Looked around and the fastest one I could see is this dude:

http://www.diodes.com/datasheets/ZXGD3003E6.pdf

Not too much data but it gets into the 2nsec range. Anyone aware of a
driver with even more testosterone?
The rise/fall times are mediocre. A little series inductive peaking
would help.

Mediocre? At high capacitive load maybe but at low loads I think they
are amazing for a 25c part. Most others including its other ZXGD300x
brethren peter out towards 10nsec for one of both slopes towards zero
capacitance.


Gate driver chips are cool, though. They have lots of off-label uses.

Oh yeah :)


Of course the ideal scenario would be a push-pull MMIC with 15V or more
supply voltage but that ain't going to happen. Same with RF switches,
even if they could take 12V they are surprisingly slow in switch action.

Ok, could roll my own, of course. But that gets to be involved and a bit
too big for this project.
What's the load? Need DC coupling/long pulses?

Pulses are under 100nsec length and duty cycle is well under 5%. Getting
DC across would be great but I am afraid I'll have to clamp that ...
somehow ... because it's a high voltage I'll have to move with that. Or
I'll let this whole thing ride on the rail. Woe to dose who toucha wid
da fingahs :)


I know how to get 6 or 7 volts of brutal sub-ns swing cheap, at zero
Iq. Could be doubled, depending. Not for public release.

7V would be a bit low, and I'd need zippy in both directions.
If you need high-side drive, a pair of my drivers could feed opposite
ends of a 1:1 transmission line transformer (or maybe a balun) to
double the swing. 12 volts for 100 ns would be no problem, edges well
below a ns.

RF parts such as baluns or obscure directional couplers with a voodoo
coefficient never scared me.


At below 5% duty cycle, you probably don't need to DC restore.

Not sure yet if I do. This high voltages acts as kind of a reference
somewhere. It's one of those circuits that most people won't even touch
with a 10ft pole.


It'll cost you a burger and a couple of beers. Zeitgeist has about 40
on tap.

I am game. But I have no idea when I get to S.F. the next time. A lot of
my clients are no longer in California, for reasons we all know, and
Villaraigosa has just made that loud and clear to companies once more :-(

Now if you ever get into this area we have a very nice Japanese
restaurant. Blue Moon and Sapporo on tap.


If pulse width is fixed, there's another way to do it: a really fast
open-drain mosfet feeding a 1:1 transformer, 12 volts or whatever you
like. The magnetizing current powers the falling edge. Also cheap.

It must remain adjustable.

Never turn down an offer from Larkin. He's promised you a half-fast solution,
and I'm sure he can deliver ;-)
Click to expand...
I am sure he can. Fast stuff is what his company mostly does and if they
didn't earn megabucks per year with this they would hardly be able to
buy a large building smack dab in the middle of a metropolis.

--
Regards, Joerg

http://www.analogconsultants.com/
 
On Fri, 19 Aug 2011 07:28:18 -0700, Joerg <invalid@invalid.invalid>
wrote:

Jim Thompson wrote:
On Thu, 18 Aug 2011 18:06:13 -0700, Joerg <invalid@invalid.invalid> wrote:

John Larkin wrote:
On Thu, 18 Aug 2011 14:01:41 -0700, Joerg <invalid@invalid.invalid
wrote:

John Larkin wrote:
On Thu, 18 Aug 2011 12:59:05 -0700, Joerg <invalid@invalid.invalid
wrote:

Folks,

Have to drive around a hundred pF or so in parallel with maybe a few
hundred ohms blazingly fast. 10-12V amplitude, transitions ideally
sub-nanosecond from 10-90% both directions. Not too boutiquish or
unobtanium (which excludes certain companies ...) and not more than a
few Dollars. Shouldn't introduce noise when low. Low quiescent current,
preferably under 20mA.

Looked around and the fastest one I could see is this dude:

http://www.diodes.com/datasheets/ZXGD3003E6.pdf

Not too much data but it gets into the 2nsec range. Anyone aware of a
driver with even more testosterone?
The rise/fall times are mediocre. A little series inductive peaking
would help.

Mediocre? At high capacitive load maybe but at low loads I think they
are amazing for a 25c part. Most others including its other ZXGD300x
brethren peter out towards 10nsec for one of both slopes towards zero
capacitance.


Gate driver chips are cool, though. They have lots of off-label uses.

Oh yeah :)


Of course the ideal scenario would be a push-pull MMIC with 15V or more
supply voltage but that ain't going to happen. Same with RF switches,
even if they could take 12V they are surprisingly slow in switch action.

Ok, could roll my own, of course. But that gets to be involved and a bit
too big for this project.
What's the load? Need DC coupling/long pulses?

Pulses are under 100nsec length and duty cycle is well under 5%. Getting
DC across would be great but I am afraid I'll have to clamp that ...
somehow ... because it's a high voltage I'll have to move with that. Or
I'll let this whole thing ride on the rail. Woe to dose who toucha wid
da fingahs :)


I know how to get 6 or 7 volts of brutal sub-ns swing cheap, at zero
Iq. Could be doubled, depending. Not for public release.

7V would be a bit low, and I'd need zippy in both directions.
If you need high-side drive, a pair of my drivers could feed opposite
ends of a 1:1 transmission line transformer (or maybe a balun) to
double the swing. 12 volts for 100 ns would be no problem, edges well
below a ns.

RF parts such as baluns or obscure directional couplers with a voodoo
coefficient never scared me.


At below 5% duty cycle, you probably don't need to DC restore.

Not sure yet if I do. This high voltages acts as kind of a reference
somewhere. It's one of those circuits that most people won't even touch
with a 10ft pole.


It'll cost you a burger and a couple of beers. Zeitgeist has about 40
on tap.

I am game. But I have no idea when I get to S.F. the next time. A lot of
my clients are no longer in California, for reasons we all know, and
Villaraigosa has just made that loud and clear to companies once more :-(

Now if you ever get into this area we have a very nice Japanese
restaurant. Blue Moon and Sapporo on tap.


If pulse width is fixed, there's another way to do it: a really fast
open-drain mosfet feeding a 1:1 transformer, 12 volts or whatever you
like. The magnetizing current powers the falling edge. Also cheap.

It must remain adjustable.

Never turn down an offer from Larkin. He's promised you a half-fast solution,
and I'm sure he can deliver ;-)


I am sure he can. Fast stuff is what his company mostly does and if they
didn't earn megabucks per year with this they would hardly be able to
buy a large building smack dab in the middle of a metropolis.
Click to expand...
It was a working fortune cookie factory. 1930's (ie, terrible)
concrete side walls, wooden floors and roof, a perfect candidate for
pancaking in the next good earthquake. It's sitting on sand, at the
edge of a liquefaction zone. We added a bunch of concrete footings and
steel frames and plywood and bolts.

You can see our place in the default Google Earth view of San
Francisco. For some odd reason, Google thinks "San Francisco" is in
the middle of the interesction of Market and Van Ness, one block away.

And we haven't had a sandstorm for as long as we've been here.

http://www.panoramio.com/photo/57596123

John
 
John Larkin wrote:
On Fri, 19 Aug 2011 07:28:18 -0700, Joerg <invalid@invalid.invalid
wrote:

Jim Thompson wrote:
On Thu, 18 Aug 2011 18:06:13 -0700, Joerg <invalid@invalid.invalid> wrote:

John Larkin wrote:
On Thu, 18 Aug 2011 14:01:41 -0700, Joerg <invalid@invalid.invalid
wrote:

John Larkin wrote:
On Thu, 18 Aug 2011 12:59:05 -0700, Joerg <invalid@invalid.invalid
wrote:

Folks,

Have to drive around a hundred pF or so in parallel with maybe a few
hundred ohms blazingly fast. 10-12V amplitude, transitions ideally
sub-nanosecond from 10-90% both directions. Not too boutiquish or
unobtanium (which excludes certain companies ...) and not more than a
few Dollars. Shouldn't introduce noise when low. Low quiescent current,
preferably under 20mA.

Looked around and the fastest one I could see is this dude:

http://www.diodes.com/datasheets/ZXGD3003E6.pdf

Not too much data but it gets into the 2nsec range. Anyone aware of a
driver with even more testosterone?
The rise/fall times are mediocre. A little series inductive peaking
would help.

Mediocre? At high capacitive load maybe but at low loads I think they
are amazing for a 25c part. Most others including its other ZXGD300x
brethren peter out towards 10nsec for one of both slopes towards zero
capacitance.


Gate driver chips are cool, though. They have lots of off-label uses.

Oh yeah :)


Of course the ideal scenario would be a push-pull MMIC with 15V or more
supply voltage but that ain't going to happen. Same with RF switches,
even if they could take 12V they are surprisingly slow in switch action.

Ok, could roll my own, of course. But that gets to be involved and a bit
too big for this project.
What's the load? Need DC coupling/long pulses?

Pulses are under 100nsec length and duty cycle is well under 5%. Getting
DC across would be great but I am afraid I'll have to clamp that ...
somehow ... because it's a high voltage I'll have to move with that. Or
I'll let this whole thing ride on the rail. Woe to dose who toucha wid
da fingahs :)


I know how to get 6 or 7 volts of brutal sub-ns swing cheap, at zero
Iq. Could be doubled, depending. Not for public release.

7V would be a bit low, and I'd need zippy in both directions.
If you need high-side drive, a pair of my drivers could feed opposite
ends of a 1:1 transmission line transformer (or maybe a balun) to
double the swing. 12 volts for 100 ns would be no problem, edges well
below a ns.

RF parts such as baluns or obscure directional couplers with a voodoo
coefficient never scared me.


At below 5% duty cycle, you probably don't need to DC restore.

Not sure yet if I do. This high voltages acts as kind of a reference
somewhere. It's one of those circuits that most people won't even touch
with a 10ft pole.


It'll cost you a burger and a couple of beers. Zeitgeist has about 40
on tap.

I am game. But I have no idea when I get to S.F. the next time. A lot of
my clients are no longer in California, for reasons we all know, and
Villaraigosa has just made that loud and clear to companies once more :-(

Now if you ever get into this area we have a very nice Japanese
restaurant. Blue Moon and Sapporo on tap.


If pulse width is fixed, there's another way to do it: a really fast
open-drain mosfet feeding a 1:1 transformer, 12 volts or whatever you
like. The magnetizing current powers the falling edge. Also cheap.

It must remain adjustable.
Never turn down an offer from Larkin. He's promised you a half-fast solution,
and I'm sure he can deliver ;-)

I am sure he can. Fast stuff is what his company mostly does and if they
didn't earn megabucks per year with this they would hardly be able to
buy a large building smack dab in the middle of a metropolis.

It was a working fortune cookie factory. 1930's (ie, terrible)
concrete side walls, wooden floors and roof, a perfect candidate for
pancaking in the next good earthquake. It's sitting on sand, at the
edge of a liquefaction zone. We added a bunch of concrete footings and
steel frames and plywood and bolts.

You can see our place in the default Google Earth view of San
Francisco. For some odd reason, Google thinks "San Francisco" is in
the middle of the interesction of Market and Van Ness, one block away.

And we haven't had a sandstorm for as long as we've been here.

http://www.panoramio.com/photo/57596123
Click to expand...
Those cherubim were on there before you bought it? They are amazingly
well preserved. I can't imagine the salty air down there to be too
friendly to concrete and plaster. The almond below probably has some
cultural meaning as well.

--
Regards, Joerg

http://www.analogconsultants.com/
 
On 08/19/2011 12:07 PM, Joerg wrote:
John Larkin wrote:
On Fri, 19 Aug 2011 07:28:18 -0700, Joerg<invalid@invalid.invalid
wrote:

Jim Thompson wrote:
On Thu, 18 Aug 2011 18:06:13 -0700, Joerg<invalid@invalid.invalid> wrote:

John Larkin wrote:
On Thu, 18 Aug 2011 14:01:41 -0700, Joerg<invalid@invalid.invalid
wrote:

John Larkin wrote:
On Thu, 18 Aug 2011 12:59:05 -0700, Joerg<invalid@invalid.invalid
wrote:

Folks,

Have to drive around a hundred pF or so in parallel with maybe a few
hundred ohms blazingly fast. 10-12V amplitude, transitions ideally
sub-nanosecond from 10-90% both directions. Not too boutiquish or
unobtanium (which excludes certain companies ...) and not more than a
few Dollars. Shouldn't introduce noise when low. Low quiescent current,
preferably under 20mA.

Looked around and the fastest one I could see is this dude:

http://www.diodes.com/datasheets/ZXGD3003E6.pdf

Not too much data but it gets into the 2nsec range. Anyone aware of a
driver with even more testosterone?
The rise/fall times are mediocre. A little series inductive peaking
would help.

Mediocre? At high capacitive load maybe but at low loads I think they
are amazing for a 25c part. Most others including its other ZXGD300x
brethren peter out towards 10nsec for one of both slopes towards zero
capacitance.


Gate driver chips are cool, though. They have lots of off-label uses.

Oh yeah :)


Of course the ideal scenario would be a push-pull MMIC with 15V or more
supply voltage but that ain't going to happen. Same with RF switches,
even if they could take 12V they are surprisingly slow in switch action.

Ok, could roll my own, of course. But that gets to be involved and a bit
too big for this project.
What's the load? Need DC coupling/long pulses?

Pulses are under 100nsec length and duty cycle is well under 5%. Getting
DC across would be great but I am afraid I'll have to clamp that ...
somehow ... because it's a high voltage I'll have to move with that. Or
I'll let this whole thing ride on the rail. Woe to dose who toucha wid
da fingahs :)


I know how to get 6 or 7 volts of brutal sub-ns swing cheap, at zero
Iq. Could be doubled, depending. Not for public release.

7V would be a bit low, and I'd need zippy in both directions.
If you need high-side drive, a pair of my drivers could feed opposite
ends of a 1:1 transmission line transformer (or maybe a balun) to
double the swing. 12 volts for 100 ns would be no problem, edges well
below a ns.

RF parts such as baluns or obscure directional couplers with a voodoo
coefficient never scared me.


At below 5% duty cycle, you probably don't need to DC restore.

Not sure yet if I do. This high voltages acts as kind of a reference
somewhere. It's one of those circuits that most people won't even touch
with a 10ft pole.


It'll cost you a burger and a couple of beers. Zeitgeist has about 40
on tap.

I am game. But I have no idea when I get to S.F. the next time. A lot of
my clients are no longer in California, for reasons we all know, and
Villaraigosa has just made that loud and clear to companies once more :-(

Now if you ever get into this area we have a very nice Japanese
restaurant. Blue Moon and Sapporo on tap.


If pulse width is fixed, there's another way to do it: a really fast
open-drain mosfet feeding a 1:1 transformer, 12 volts or whatever you
like. The magnetizing current powers the falling edge. Also cheap.

It must remain adjustable.
Never turn down an offer from Larkin. He's promised you a half-fast solution,
and I'm sure he can deliver ;-)

I am sure he can. Fast stuff is what his company mostly does and if they
didn't earn megabucks per year with this they would hardly be able to
buy a large building smack dab in the middle of a metropolis.

It was a working fortune cookie factory. 1930's (ie, terrible)
concrete side walls, wooden floors and roof, a perfect candidate for
pancaking in the next good earthquake. It's sitting on sand, at the
edge of a liquefaction zone. We added a bunch of concrete footings and
steel frames and plywood and bolts.

You can see our place in the default Google Earth view of San
Francisco. For some odd reason, Google thinks "San Francisco" is in
the middle of the interesction of Market and Van Ness, one block away.

And we haven't had a sandstorm for as long as we've been here.

http://www.panoramio.com/photo/57596123


Those cherubim were on there before you bought it? They are amazingly
well preserved. I can't imagine the salty air down there to be too
friendly to concrete and plaster. The almond below probably has some
cultural meaning as well.
Click to expand...
Almond? I thought it was a tamale.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net
 
On Fri, 19 Aug 2011 09:07:39 -0700, Joerg <invalid@invalid.invalid>
wrote:

John Larkin wrote:
On Fri, 19 Aug 2011 07:28:18 -0700, Joerg <invalid@invalid.invalid
wrote:

Jim Thompson wrote:
On Thu, 18 Aug 2011 18:06:13 -0700, Joerg <invalid@invalid.invalid> wrote:

John Larkin wrote:
On Thu, 18 Aug 2011 14:01:41 -0700, Joerg <invalid@invalid.invalid
wrote:

John Larkin wrote:
On Thu, 18 Aug 2011 12:59:05 -0700, Joerg <invalid@invalid.invalid
wrote:

Folks,

Have to drive around a hundred pF or so in parallel with maybe a few
hundred ohms blazingly fast. 10-12V amplitude, transitions ideally
sub-nanosecond from 10-90% both directions. Not too boutiquish or
unobtanium (which excludes certain companies ...) and not more than a
few Dollars. Shouldn't introduce noise when low. Low quiescent current,
preferably under 20mA.

Looked around and the fastest one I could see is this dude:

http://www.diodes.com/datasheets/ZXGD3003E6.pdf

Not too much data but it gets into the 2nsec range. Anyone aware of a
driver with even more testosterone?
The rise/fall times are mediocre. A little series inductive peaking
would help.

Mediocre? At high capacitive load maybe but at low loads I think they
are amazing for a 25c part. Most others including its other ZXGD300x
brethren peter out towards 10nsec for one of both slopes towards zero
capacitance.


Gate driver chips are cool, though. They have lots of off-label uses.

Oh yeah :)


Of course the ideal scenario would be a push-pull MMIC with 15V or more
supply voltage but that ain't going to happen. Same with RF switches,
even if they could take 12V they are surprisingly slow in switch action.

Ok, could roll my own, of course. But that gets to be involved and a bit
too big for this project.
What's the load? Need DC coupling/long pulses?

Pulses are under 100nsec length and duty cycle is well under 5%. Getting
DC across would be great but I am afraid I'll have to clamp that ...
somehow ... because it's a high voltage I'll have to move with that. Or
I'll let this whole thing ride on the rail. Woe to dose who toucha wid
da fingahs :)


I know how to get 6 or 7 volts of brutal sub-ns swing cheap, at zero
Iq. Could be doubled, depending. Not for public release.

7V would be a bit low, and I'd need zippy in both directions.
If you need high-side drive, a pair of my drivers could feed opposite
ends of a 1:1 transmission line transformer (or maybe a balun) to
double the swing. 12 volts for 100 ns would be no problem, edges well
below a ns.

RF parts such as baluns or obscure directional couplers with a voodoo
coefficient never scared me.


At below 5% duty cycle, you probably don't need to DC restore.

Not sure yet if I do. This high voltages acts as kind of a reference
somewhere. It's one of those circuits that most people won't even touch
with a 10ft pole.


It'll cost you a burger and a couple of beers. Zeitgeist has about 40
on tap.

I am game. But I have no idea when I get to S.F. the next time. A lot of
my clients are no longer in California, for reasons we all know, and
Villaraigosa has just made that loud and clear to companies once more :-(

Now if you ever get into this area we have a very nice Japanese
restaurant. Blue Moon and Sapporo on tap.


If pulse width is fixed, there's another way to do it: a really fast
open-drain mosfet feeding a 1:1 transformer, 12 volts or whatever you
like. The magnetizing current powers the falling edge. Also cheap.

It must remain adjustable.
Never turn down an offer from Larkin. He's promised you a half-fast solution,
and I'm sure he can deliver ;-)

I am sure he can. Fast stuff is what his company mostly does and if they
didn't earn megabucks per year with this they would hardly be able to
buy a large building smack dab in the middle of a metropolis.

It was a working fortune cookie factory. 1930's (ie, terrible)
concrete side walls, wooden floors and roof, a perfect candidate for
pancaking in the next good earthquake. It's sitting on sand, at the
edge of a liquefaction zone. We added a bunch of concrete footings and
steel frames and plywood and bolts.

You can see our place in the default Google Earth view of San
Francisco. For some odd reason, Google thinks "San Francisco" is in
the middle of the interesction of Market and Van Ness, one block away.

And we haven't had a sandstorm for as long as we've been here.

http://www.panoramio.com/photo/57596123


Those cherubim were on there before you bought it? They are amazingly
well preserved. I can't imagine the salty air down there to be too
friendly to concrete and plaster. The almond below probably has some
cultural meaning as well.
Click to expand...
They are original, and we just cleaned them up and repainted. No
architect would dare do anything this cool any more.

The salty fog is out west, near the ocean. Everything rusts out there.

The bummer is that it's a wooden building that looks up at Sutro
Tower, 22 megawatts of AM/FM/TV/whatever. The EMI is ghastly.

John
 
John Larkin wrote:
On Fri, 19 Aug 2011 09:07:39 -0700, Joerg <invalid@invalid.invalid
wrote:

John Larkin wrote:
On Fri, 19 Aug 2011 07:28:18 -0700, Joerg <invalid@invalid.invalid
wrote:

Jim Thompson wrote:
On Thu, 18 Aug 2011 18:06:13 -0700, Joerg <invalid@invalid.invalid> wrote:

John Larkin wrote:
On Thu, 18 Aug 2011 14:01:41 -0700, Joerg <invalid@invalid.invalid
wrote:

John Larkin wrote:
On Thu, 18 Aug 2011 12:59:05 -0700, Joerg <invalid@invalid.invalid
wrote:

Folks,

Have to drive around a hundred pF or so in parallel with maybe a few
hundred ohms blazingly fast. 10-12V amplitude, transitions ideally
sub-nanosecond from 10-90% both directions. Not too boutiquish or
unobtanium (which excludes certain companies ...) and not more than a
few Dollars. Shouldn't introduce noise when low. Low quiescent current,
preferably under 20mA.

Looked around and the fastest one I could see is this dude:

http://www.diodes.com/datasheets/ZXGD3003E6.pdf

Not too much data but it gets into the 2nsec range. Anyone aware of a
driver with even more testosterone?
The rise/fall times are mediocre. A little series inductive peaking
would help.

Mediocre? At high capacitive load maybe but at low loads I think they
are amazing for a 25c part. Most others including its other ZXGD300x
brethren peter out towards 10nsec for one of both slopes towards zero
capacitance.


Gate driver chips are cool, though. They have lots of off-label uses.

Oh yeah :)


Of course the ideal scenario would be a push-pull MMIC with 15V or more
supply voltage but that ain't going to happen. Same with RF switches,
even if they could take 12V they are surprisingly slow in switch action.

Ok, could roll my own, of course. But that gets to be involved and a bit
too big for this project.
What's the load? Need DC coupling/long pulses?

Pulses are under 100nsec length and duty cycle is well under 5%. Getting
DC across would be great but I am afraid I'll have to clamp that ...
somehow ... because it's a high voltage I'll have to move with that. Or
I'll let this whole thing ride on the rail. Woe to dose who toucha wid
da fingahs :)


I know how to get 6 or 7 volts of brutal sub-ns swing cheap, at zero
Iq. Could be doubled, depending. Not for public release.

7V would be a bit low, and I'd need zippy in both directions.
If you need high-side drive, a pair of my drivers could feed opposite
ends of a 1:1 transmission line transformer (or maybe a balun) to
double the swing. 12 volts for 100 ns would be no problem, edges well
below a ns.

RF parts such as baluns or obscure directional couplers with a voodoo
coefficient never scared me.


At below 5% duty cycle, you probably don't need to DC restore.

Not sure yet if I do. This high voltages acts as kind of a reference
somewhere. It's one of those circuits that most people won't even touch
with a 10ft pole.


It'll cost you a burger and a couple of beers. Zeitgeist has about 40
on tap.

I am game. But I have no idea when I get to S.F. the next time. A lot of
my clients are no longer in California, for reasons we all know, and
Villaraigosa has just made that loud and clear to companies once more :-(

Now if you ever get into this area we have a very nice Japanese
restaurant. Blue Moon and Sapporo on tap.


If pulse width is fixed, there's another way to do it: a really fast
open-drain mosfet feeding a 1:1 transformer, 12 volts or whatever you
like. The magnetizing current powers the falling edge. Also cheap.

It must remain adjustable.
Never turn down an offer from Larkin. He's promised you a half-fast solution,
and I'm sure he can deliver ;-)

I am sure he can. Fast stuff is what his company mostly does and if they
didn't earn megabucks per year with this they would hardly be able to
buy a large building smack dab in the middle of a metropolis.
It was a working fortune cookie factory. 1930's (ie, terrible)
concrete side walls, wooden floors and roof, a perfect candidate for
pancaking in the next good earthquake. It's sitting on sand, at the
edge of a liquefaction zone. We added a bunch of concrete footings and
steel frames and plywood and bolts.

You can see our place in the default Google Earth view of San
Francisco. For some odd reason, Google thinks "San Francisco" is in
the middle of the interesction of Market and Van Ness, one block away.

And we haven't had a sandstorm for as long as we've been here.

http://www.panoramio.com/photo/57596123

Those cherubim were on there before you bought it? They are amazingly
well preserved. I can't imagine the salty air down there to be too
friendly to concrete and plaster. The almond below probably has some
cultural meaning as well.

They are original, and we just cleaned them up and repainted. No
architect would dare do anything this cool any more.

The salty fog is out west, near the ocean. Everything rusts out there.

The bummer is that it's a wooden building that looks up at Sutro
Tower, 22 megawatts of AM/FM/TV/whatever. The EMI is ghastly.
Click to expand...
Look at the bright side: If you'd need a sensor somewhere out of reach
of power you can just add a loop, some diodes, and it'll be supplied
with power until Sutro Tower keels over :)

If I'd needed a quiet lab place I'd find something in the outbacks of
Alabama or similar states. Then you are neither bothered by RF fields
nor by biz-hostile politicians.

--
Regards, Joerg

http://www.analogconsultants.com/
 
On 20/08/2011 2:46 AM, Joerg wrote:
John Larkin wrote:
On Fri, 19 Aug 2011 09:07:39 -0700, Joerg<invalid@invalid.invalid
wrote:

John Larkin wrote:
On Fri, 19 Aug 2011 07:28:18 -0700, Joerg<invalid@invalid.invalid
wrote:

Jim Thompson wrote:
On Thu, 18 Aug 2011 18:06:13 -0700, Joerg<invalid@invalid.invalid> wrote:

John Larkin wrote:
On Thu, 18 Aug 2011 14:01:41 -0700, Joerg<invalid@invalid.invalid
wrote:

John Larkin wrote:
On Thu, 18 Aug 2011 12:59:05 -0700, Joerg<invalid@invalid.invalid
wrote:

Folks,

Have to drive around a hundred pF or so in parallel with maybe a few
hundred ohms blazingly fast. 10-12V amplitude, transitions ideally
sub-nanosecond from 10-90% both directions. Not too boutiquish or
unobtanium (which excludes certain companies ...) and not more than a
few Dollars. Shouldn't introduce noise when low. Low quiescent current,
preferably under 20mA.

Looked around and the fastest one I could see is this dude:

http://www.diodes.com/datasheets/ZXGD3003E6.pdf

Not too much data but it gets into the 2nsec range. Anyone aware of a
driver with even more testosterone?
The rise/fall times are mediocre. A little series inductive peaking
would help.

Mediocre? At high capacitive load maybe but at low loads I think they
are amazing for a 25c part. Most others including its other ZXGD300x
brethren peter out towards 10nsec for one of both slopes towards zero
capacitance.


Gate driver chips are cool, though. They have lots of off-label uses.

Oh yeah :)


Of course the ideal scenario would be a push-pull MMIC with 15V or more
supply voltage but that ain't going to happen. Same with RF switches,
even if they could take 12V they are surprisingly slow in switch action.

Ok, could roll my own, of course. But that gets to be involved and a bit
too big for this project.
What's the load? Need DC coupling/long pulses?

Pulses are under 100nsec length and duty cycle is well under 5%. Getting
DC across would be great but I am afraid I'll have to clamp that ...
somehow ... because it's a high voltage I'll have to move with that. Or
I'll let this whole thing ride on the rail. Woe to dose who toucha wid
da fingahs :)


I know how to get 6 or 7 volts of brutal sub-ns swing cheap, at zero
Iq. Could be doubled, depending. Not for public release.

7V would be a bit low, and I'd need zippy in both directions.
If you need high-side drive, a pair of my drivers could feed opposite
ends of a 1:1 transmission line transformer (or maybe a balun) to
double the swing. 12 volts for 100 ns would be no problem, edges well
below a ns.

RF parts such as baluns or obscure directional couplers with a voodoo
coefficient never scared me.


At below 5% duty cycle, you probably don't need to DC restore.

Not sure yet if I do. This high voltages acts as kind of a reference
somewhere. It's one of those circuits that most people won't even touch
with a 10ft pole.


It'll cost you a burger and a couple of beers. Zeitgeist has about 40
on tap.

I am game. But I have no idea when I get to S.F. the next time. A lot of
my clients are no longer in California, for reasons we all know, and
Villaraigosa has just made that loud and clear to companies once more :-(

Now if you ever get into this area we have a very nice Japanese
restaurant. Blue Moon and Sapporo on tap.


If pulse width is fixed, there's another way to do it: a really fast
open-drain mosfet feeding a 1:1 transformer, 12 volts or whatever you
like. The magnetizing current powers the falling edge. Also cheap.

It must remain adjustable.
Never turn down an offer from Larkin. He's promised you a half-fast solution,
and I'm sure he can deliver ;-)

I am sure he can. Fast stuff is what his company mostly does and if they
didn't earn megabucks per year with this they would hardly be able to
buy a large building smack dab in the middle of a metropolis.
It was a working fortune cookie factory. 1930's (ie, terrible)
concrete side walls, wooden floors and roof, a perfect candidate for
pancaking in the next good earthquake. It's sitting on sand, at the
edge of a liquefaction zone. We added a bunch of concrete footings and
steel frames and plywood and bolts.

You can see our place in the default Google Earth view of San
Francisco. For some odd reason, Google thinks "San Francisco" is in
the middle of the interesction of Market and Van Ness, one block away.

And we haven't had a sandstorm for as long as we've been here.

http://www.panoramio.com/photo/57596123

Those cherubim were on there before you bought it? They are amazingly
well preserved. I can't imagine the salty air down there to be too
friendly to concrete and plaster. The almond below probably has some
cultural meaning as well.

They are original, and we just cleaned them up and repainted. No
architect would dare do anything this cool any more.

The salty fog is out west, near the ocean. Everything rusts out there.

The bummer is that it's a wooden building that looks up at Sutro
Tower, 22 megawatts of AM/FM/TV/whatever. The EMI is ghastly.


Look at the bright side: If you'd need a sensor somewhere out of reach
of power you can just add a loop, some diodes, and it'll be supplied
with power until Sutro Tower keels over :)

If I'd needed a quiet lab place I'd find something in the outbacks of
Alabama or similar states. Then you are neither bothered by RF fields
nor by biz-hostile politicians.
Click to expand...
On the other hand, the chances of being able to hire locally resident
expert help wouldn't be that great. And they are Baptists - perhaps not
as sincerely Baptist as the inhabitants of Urk are Calvinist, but still
pretty inflexible - so you'd run the risk of being rejected as a
schismatic Lutheran.

--
Bill Sloman, Nijmegen
 
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