Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
MOSFETs are getting better, year by year,
see my 25-year Rds * Qgd scatterplot.
https://www.dropbox.com/s/l5f0h1fp7pynwus/MOSFET_scatterplot%2C%20Qgd%20FOM.pdf?dl=0
Winfield Hill <winfieldhill@yahoo.com> wrote:
MOSFETs are getting better, year by year,
see my 25-year Rds * Qgd scatterplot.
https://www.dropbox.com/s/l5f0h1fp7pynwus/MOSFET_scatterplot%2C%20Qgd%20FOM.pdf?dl=0
And exotica, phemts and now Sic and GaN,
totally blows away mosfets.
John Larkin wrote...
Winfield Hill wrote:
John Larkin wrote...
Winfield Hill wrote:
MOSFETs are getting better, year by year,
see my 25-year Rds * Qgd scatterplot.
https://www.dropbox.com/s/l5f0h1fp7pynwus/MOSFET_scatterplot%2C%20Qgd%20FOM.pdf?dl=0
And exotica, phemts and now Sic and GaN,
totally blows away mosfets.
Actually, no, they're on my spreadsheet as well.
Blow away the old MOSFETs, yes, but not the new
super-junction FETs, that represent about half
of the new ones in my table. For example, most
SiC parts are nested with the best super-junction
parts, except for a few that stand out and are
1.5 to 2x better. There's a specific SiC that's
spectacular, but it has power-handling issues.
Is any mosfet comparable to the Cree C2M0280120D?
I've pushed that one to the limit.
That's my favorite one, that I was talking about.
But its 0.6-ohm Ron (when hot) is rather high, and
its weak 62W case rating is rather low. Also, it
comes in a wastefully-huge TO-247 package. But,
hey, it's not expensive, and makes great pulses.
Winfield Hill wrote:
John Larkin wrote...
Winfield Hill wrote:
MOSFETs are getting better, year by year,
see my 25-year Rds * Qgd scatterplot.
https://www.dropbox.com/s/l5f0h1fp7pynwus/MOSFET_scatterplot%2C%20Qgd%20FOM.pdf?dl=0
And exotica, phemts and now Sic and GaN,
totally blows away mosfets.
Actually, no, they're on my spreadsheet as well.
Blow away the old MOSFETs, yes, but not the new
super-junction FETs, that represent about half
of the new ones in my table. For example, most
SiC parts are nested with the best super-junction
parts, except for a few that stand out and are
1.5 to 2x better. There's a specific SiC that's
spectacular, but it has power-handling issues.
Is any mosfet comparable to the Cree C2M0280120D?
I've pushed that one to the limit.
John Larkin wrote...
Winfield Hill <winfieldhill@yahoo.com> wrote:
MOSFETs are getting better, year by year,
see my 25-year Rds * Qgd scatterplot.
https://www.dropbox.com/s/l5f0h1fp7pynwus/MOSFET_scatterplot%2C%20Qgd%20FOM.pdf?dl=0
And exotica, phemts and now Sic and GaN,
totally blows away mosfets.
Actually, no, they're on my spreadsheet as well.
Blow away the old MOSFETs, yes, but not the new
super-junction FETs, that represent about half
of the new ones in my table. For example, most
SiC parts are nested with the best super-junction
parts, except for a few that stand out and are
1.5 to 2x better. There's a specific SiC that's
spectacular, but it has power-handling issues.
On Tue, 18 Jun 2019 12:28:25 -0700, John Larkin
jjlarkin@highland_snip_technology.com> wrote:
On 18 Jun 2019 12:22:14 -0700, Winfield Hill <winfieldhill@yahoo.com
wrote:
John Larkin wrote...
Winfield Hill wrote:
John Larkin wrote...
Winfield Hill wrote:
MOSFETs are getting better, year by year,
see my 25-year Rds * Qgd scatterplot.
https://www.dropbox.com/s/l5f0h1fp7pynwus/MOSFET_scatterplot%2C%20Qgd%20FOM.pdf?dl=0
And exotica, phemts and now Sic and GaN,
totally blows away mosfets.
Actually, no, they're on my spreadsheet as well.
Blow away the old MOSFETs, yes, but not the new
super-junction FETs, that represent about half
of the new ones in my table. For example, most
SiC parts are nested with the best super-junction
parts, except for a few that stand out and are
1.5 to 2x better. There's a specific SiC that's
spectacular, but it has power-handling issues.
Is any mosfet comparable to the Cree C2M0280120D?
I've pushed that one to the limit.
That's my favorite one, that I was talking about.
But its 0.6-ohm Ron (when hot) is rather high, and
its weak 62W case rating is rather low. Also, it
comes in a wastefully-huge TO-247 package. But,
hey, it's not expensive, and makes great pulses.
The chip is tiny for the package.
https://www.dropbox.com/s/hnu2b7qlfw98bwq/Cree_Chip.JPG?dl=0
Its RDS-on tempco is awful, close to thermal runaway turf. There's a
similar ST fet that has a much flatter Rds tempco.
The wide bandgap parts blow aray silicon MOSFETs at HIGH(er) voltages.
At low voltage, say, 100V and below, silicon have much lower RdsOn,
bigger die (important for surge current) and low enough voltage that
the shitty diode reverse recovery time isn't much of an issue.
And the price is always higher at the moment for the same size die of
SiC than it is for Si. Hopefully that will change someday soon.
SiC is awesome stuff though. I use both SiC and Si.
On 18 Jun 2019 12:22:14 -0700, Winfield Hill <winfieldhill@yahoo.com
wrote:
John Larkin wrote...
Winfield Hill wrote:
John Larkin wrote...
Winfield Hill wrote:
MOSFETs are getting better, year by year,
see my 25-year Rds * Qgd scatterplot.
https://www.dropbox.com/s/l5f0h1fp7pynwus/MOSFET_scatterplot%2C%20Qgd%20FOM.pdf?dl=0
And exotica, phemts and now Sic and GaN,
totally blows away mosfets.
Actually, no, they're on my spreadsheet as well.
Blow away the old MOSFETs, yes, but not the new
super-junction FETs, that represent about half
of the new ones in my table. For example, most
SiC parts are nested with the best super-junction
parts, except for a few that stand out and are
1.5 to 2x better. There's a specific SiC that's
spectacular, but it has power-handling issues.
Is any mosfet comparable to the Cree C2M0280120D?
I've pushed that one to the limit.
That's my favorite one, that I was talking about.
But its 0.6-ohm Ron (when hot) is rather high, and
its weak 62W case rating is rather low. Also, it
comes in a wastefully-huge TO-247 package. But,
hey, it's not expensive, and makes great pulses.
The chip is tiny for the package.
https://www.dropbox.com/s/hnu2b7qlfw98bwq/Cree_Chip.JPG?dl=0
Its RDS-on tempco is awful, close to thermal runaway turf. There's a
similar ST fet that has a much flatter Rds tempco.
On Tue, 18 Jun 2019 05:57:12 -0700, Winfield Hill said:
MOSFETs are getting better, year by year
So is a lot of stuff. Hardly a revelation!
On Tue, 18 Jun 2019 14:08:00 -0700, boB <boB@K7IQ.com> wrote:
On Tue, 18 Jun 2019 12:28:25 -0700, John Larkin
jjlarkin@highland_snip_technology.com> wrote:
On 18 Jun 2019 12:22:14 -0700, Winfield Hill <winfieldhill@yahoo.com
wrote:
John Larkin wrote...
Winfield Hill wrote:
John Larkin wrote...
Winfield Hill wrote:
MOSFETs are getting better, year by year,
see my 25-year Rds * Qgd scatterplot.
https://www.dropbox.com/s/l5f0h1fp7pynwus/MOSFET_scatterplot%2C%20Qgd%20FOM.pdf?dl=0
And exotica, phemts and now Sic and GaN,
totally blows away mosfets.
Actually, no, they're on my spreadsheet as well.
Blow away the old MOSFETs, yes, but not the new
super-junction FETs, that represent about half
of the new ones in my table. For example, most
SiC parts are nested with the best super-junction
parts, except for a few that stand out and are
1.5 to 2x better. There's a specific SiC that's
spectacular, but it has power-handling issues.
Is any mosfet comparable to the Cree C2M0280120D?
I've pushed that one to the limit.
That's my favorite one, that I was talking about.
But its 0.6-ohm Ron (when hot) is rather high, and
its weak 62W case rating is rather low. Also, it
comes in a wastefully-huge TO-247 package. But,
hey, it's not expensive, and makes great pulses.
The chip is tiny for the package.
https://www.dropbox.com/s/hnu2b7qlfw98bwq/Cree_Chip.JPG?dl=0
Its RDS-on tempco is awful, close to thermal runaway turf. There's a
similar ST fet that has a much flatter Rds tempco.
The wide bandgap parts blow aray silicon MOSFETs at HIGH(er) voltages.
At low voltage, say, 100V and below, silicon have much lower RdsOn,
bigger die (important for surge current) and low enough voltage that
the shitty diode reverse recovery time isn't much of an issue.
And the price is always higher at the moment for the same size die of
SiC than it is for Si. Hopefully that will change someday soon.
SiC is awesome stuff though. I use both SiC and Si.
The substrate diode in the Cree is awful, slow turn-on. The Spice
model lies about that.
On Tue, 18 Jun 2019 14:23:58 -0700, John Larkin
jjlarkin@highland_snip_technology.com> wrote:
On Tue, 18 Jun 2019 14:08:00 -0700, boB <boB@K7IQ.com> wrote:
On Tue, 18 Jun 2019 12:28:25 -0700, John Larkin
jjlarkin@highland_snip_technology.com> wrote:
On 18 Jun 2019 12:22:14 -0700, Winfield Hill <winfieldhill@yahoo.com
wrote:
John Larkin wrote...
Winfield Hill wrote:
John Larkin wrote...
Winfield Hill wrote:
MOSFETs are getting better, year by year,
see my 25-year Rds * Qgd scatterplot.
https://www.dropbox.com/s/l5f0h1fp7pynwus/MOSFET_scatterplot%2C%20Qgd%20FOM.pdf?dl=0
And exotica, phemts and now Sic and GaN,
totally blows away mosfets.
Actually, no, they're on my spreadsheet as well.
Blow away the old MOSFETs, yes, but not the new
super-junction FETs, that represent about half
of the new ones in my table. For example, most
SiC parts are nested with the best super-junction
parts, except for a few that stand out and are
1.5 to 2x better. There's a specific SiC that's
spectacular, but it has power-handling issues.
Is any mosfet comparable to the Cree C2M0280120D?
I've pushed that one to the limit.
That's my favorite one, that I was talking about.
But its 0.6-ohm Ron (when hot) is rather high, and
its weak 62W case rating is rather low. Also, it
comes in a wastefully-huge TO-247 package. But,
hey, it's not expensive, and makes great pulses.
The chip is tiny for the package.
https://www.dropbox.com/s/hnu2b7qlfw98bwq/Cree_Chip.JPG?dl=0
Its RDS-on tempco is awful, close to thermal runaway turf. There's a
similar ST fet that has a much flatter Rds tempco.
The wide bandgap parts blow aray silicon MOSFETs at HIGH(er) voltages.
At low voltage, say, 100V and below, silicon have much lower RdsOn,
bigger die (important for surge current) and low enough voltage that
the shitty diode reverse recovery time isn't much of an issue.
And the price is always higher at the moment for the same size die of
SiC than it is for Si. Hopefully that will change someday soon.
SiC is awesome stuff though. I use both SiC and Si.
The substrate diode in the Cree is awful, slow turn-on. The Spice
model lies about that.
Really ? I think I saw you or someone else say that. I have some
Cree SiC FETs now that I am going to try in place of the ROHM parts
that are already working awesome. They are cheaper than the Rohm's
but also have a smaller die I believe.
Silicon, for hard switching HV power is unusable for me.
I have been all hot for GaN parts since about 2005 but still, there
aren't any parts I can use for several hundred volts like there are
for SiC FETs.
On Tue, 18 Jun 2019 16:33:25 -0700, boB <boB@K7IQ.com> wrote:
On Tue, 18 Jun 2019 14:23:58 -0700, John Larkin
jjlarkin@highland_snip_technology.com> wrote:
On Tue, 18 Jun 2019 14:08:00 -0700, boB <boB@K7IQ.com> wrote:
On Tue, 18 Jun 2019 12:28:25 -0700, John Larkin
jjlarkin@highland_snip_technology.com> wrote:
On 18 Jun 2019 12:22:14 -0700, Winfield Hill <winfieldhill@yahoo.com
wrote:
John Larkin wrote...
Winfield Hill wrote:
John Larkin wrote...
Winfield Hill wrote:
MOSFETs are getting better, year by year,
see my 25-year Rds * Qgd scatterplot.
https://www.dropbox.com/s/l5f0h1fp7pynwus/MOSFET_scatterplot%2C%20Qgd%20FOM.pdf?dl=0
And exotica, phemts and now Sic and GaN,
totally blows away mosfets.
Actually, no, they're on my spreadsheet as well.
Blow away the old MOSFETs, yes, but not the new
super-junction FETs, that represent about half
of the new ones in my table. For example, most
SiC parts are nested with the best super-junction
parts, except for a few that stand out and are
1.5 to 2x better. There's a specific SiC that's
spectacular, but it has power-handling issues.
Is any mosfet comparable to the Cree C2M0280120D?
I've pushed that one to the limit.
That's my favorite one, that I was talking about.
But its 0.6-ohm Ron (when hot) is rather high, and
its weak 62W case rating is rather low. Also, it
comes in a wastefully-huge TO-247 package. But,
hey, it's not expensive, and makes great pulses.
The chip is tiny for the package.
https://www.dropbox.com/s/hnu2b7qlfw98bwq/Cree_Chip.JPG?dl=0
Its RDS-on tempco is awful, close to thermal runaway turf. There's a
similar ST fet that has a much flatter Rds tempco.
The wide bandgap parts blow aray silicon MOSFETs at HIGH(er) voltages.
At low voltage, say, 100V and below, silicon have much lower RdsOn,
bigger die (important for surge current) and low enough voltage that
the shitty diode reverse recovery time isn't much of an issue.
And the price is always higher at the moment for the same size die of
SiC than it is for Si. Hopefully that will change someday soon.
SiC is awesome stuff though. I use both SiC and Si.
The substrate diode in the Cree is awful, slow turn-on. The Spice
model lies about that.
Really ? I think I saw you or someone else say that. I have some
Cree SiC FETs now that I am going to try in place of the ROHM parts
that are already working awesome. They are cheaper than the Rohm's
but also have a smaller die I believe.
The Cree parts have nice low gate series resistance, so they switch
wicked fast... if you can drive the gates hard enough. A bit of series
inductance really helps. Some other SiC parts have absurd gate
resistances.
Silicon, for hard switching HV power is unusable for me.
I have been all hot for GaN parts since about 2005 but still, there
aren't any parts I can use for several hundred volts like there are
for SiC FETs.
We are having good luck with the EPC BGA GaN parts as super fast
switches. Pain to assemble, but electrically great. Unlike SiC, they
are happy with 4 or 5 volts of gate drive.
https://www.dropbox.com/s/k1k4i1r2nhuhnyk/T577_40V_Pulse.jpg?raw=1
(40 volt supply, 50r out, loaded to make 20 volts)
Gotta find a use for that circuit.
On Tuesday, June 18, 2019 at 4:33:28 PM UTC-7, boB wrote:
Silicon, for hard switching HV power is unusable for me.
Well, except maybe for big thyristors; a full 8-inch wafer
2kV 4kA switch would be hard to replace in SiC.
Still, thyristor turnoffs aren't a pleasant subject, and
the old horizontal output transistors were TERRIBLE
switches at HV (but they could tolerate the HV
after switching OFF at a moderate voltage).
On Tue, 18 Jun 2019 17:29:01 -0700, John Larkin
jjlarkin@highland_snip_technology.com> wrote:
On Tue, 18 Jun 2019 16:33:25 -0700, boB <boB@K7IQ.com> wrote:
On Tue, 18 Jun 2019 14:23:58 -0700, John Larkin
jjlarkin@highland_snip_technology.com> wrote:
On Tue, 18 Jun 2019 14:08:00 -0700, boB <boB@K7IQ.com> wrote:
On Tue, 18 Jun 2019 12:28:25 -0700, John Larkin
jjlarkin@highland_snip_technology.com> wrote:
On 18 Jun 2019 12:22:14 -0700, Winfield Hill <winfieldhill@yahoo.com
wrote:
John Larkin wrote...
Winfield Hill wrote:
John Larkin wrote...
Winfield Hill wrote:
MOSFETs are getting better, year by year,
see my 25-year Rds * Qgd scatterplot.
https://www.dropbox.com/s/l5f0h1fp7pynwus/MOSFET_scatterplot%2C%20Qgd%20FOM.pdf?dl=0
And exotica, phemts and now Sic and GaN,
totally blows away mosfets.
Actually, no, they're on my spreadsheet as well.
Blow away the old MOSFETs, yes, but not the new
super-junction FETs, that represent about half
of the new ones in my table. For example, most
SiC parts are nested with the best super-junction
parts, except for a few that stand out and are
1.5 to 2x better. There's a specific SiC that's
spectacular, but it has power-handling issues.
Is any mosfet comparable to the Cree C2M0280120D?
I've pushed that one to the limit.
That's my favorite one, that I was talking about.
But its 0.6-ohm Ron (when hot) is rather high, and
its weak 62W case rating is rather low. Also, it
comes in a wastefully-huge TO-247 package. But,
hey, it's not expensive, and makes great pulses.
The chip is tiny for the package.
https://www.dropbox.com/s/hnu2b7qlfw98bwq/Cree_Chip.JPG?dl=0
Its RDS-on tempco is awful, close to thermal runaway turf. There's a
similar ST fet that has a much flatter Rds tempco.
The wide bandgap parts blow aray silicon MOSFETs at HIGH(er) voltages.
At low voltage, say, 100V and below, silicon have much lower RdsOn,
bigger die (important for surge current) and low enough voltage that
the shitty diode reverse recovery time isn't much of an issue.
And the price is always higher at the moment for the same size die of
SiC than it is for Si. Hopefully that will change someday soon.
SiC is awesome stuff though. I use both SiC and Si.
The substrate diode in the Cree is awful, slow turn-on. The Spice
model lies about that.
Really ? I think I saw you or someone else say that. I have some
Cree SiC FETs now that I am going to try in place of the ROHM parts
that are already working awesome. They are cheaper than the Rohm's
but also have a smaller die I believe.
The Cree parts have nice low gate series resistance, so they switch
wicked fast... if you can drive the gates hard enough. A bit of series
inductance really helps. Some other SiC parts have absurd gate
resistances.
The next generations of Rohm SiC FETs have MUCH lower gate resistance.
10 or 20 times less and lower gate charge as well. Smaller die for
the same RdsOn but that's OK because we'd be using a lower RdsOn part
anyway, which has a better short current time spec.
The frequencies that I am running these things at, whcih is less than
50 kHz at the moment, is fairly easy. The newer generations require
less gate voltage for full turn on as well. Same with the
Cree/Wolfspeed parts. 15V recommended rather than 20V.
I also use negative drive when possible but SiC parts are kind of
picky and don't want to exceed their ratings for long life.
Silicon, for hard switching HV power is unusable for me.
I have been all hot for GaN parts since about 2005 but still, there
aren't any parts I can use for several hundred volts like there are
for SiC FETs.
We are having good luck with the EPC BGA GaN parts as super fast
switches. Pain to assemble, but electrically great. Unlike SiC, they
are happy with 4 or 5 volts of gate drive.
https://www.dropbox.com/s/k1k4i1r2nhuhnyk/T577_40V_Pulse.jpg?raw=1
(40 volt supply, 50r out, loaded to make 20 volts)
Gotta find a use for that circuit.
Would be Interested to see the drive circuit for that.
That's kinda private. But regular cmos logic chips can drive low-side
GaN fets. ACT maybe. All three sections of NL37WZ16US in parallel is
awesome.
The high-side driver in a GaN totem pole is harder.
Texas LMG1020 is also fast option.
On Tue, 18 Jun 2019 20:45:04 -0700, boB <boB@K7IQ.com> wrote:
On Tue, 18 Jun 2019 17:29:01 -0700, John Larkin
jjlarkin@highland_snip_technology.com> wrote:
On Tue, 18 Jun 2019 16:33:25 -0700, boB <boB@K7IQ.com> wrote:
On Tue, 18 Jun 2019 14:23:58 -0700, John Larkin
jjlarkin@highland_snip_technology.com> wrote:
On Tue, 18 Jun 2019 14:08:00 -0700, boB <boB@K7IQ.com> wrote:
On Tue, 18 Jun 2019 12:28:25 -0700, John Larkin
jjlarkin@highland_snip_technology.com> wrote:
On 18 Jun 2019 12:22:14 -0700, Winfield Hill <winfieldhill@yahoo.com
wrote:
John Larkin wrote...
Winfield Hill wrote:
John Larkin wrote...
Winfield Hill wrote:
MOSFETs are getting better, year by year,
see my 25-year Rds * Qgd scatterplot.
https://www.dropbox.com/s/l5f0h1fp7pynwus/MOSFET_scatterplot%2C%20Qgd%20FOM.pdf?dl=0
And exotica, phemts and now Sic and GaN,
totally blows away mosfets.
Actually, no, they're on my spreadsheet as well.
Blow away the old MOSFETs, yes, but not the new
super-junction FETs, that represent about half
of the new ones in my table. For example, most
SiC parts are nested with the best super-junction
parts, except for a few that stand out and are
1.5 to 2x better. There's a specific SiC that's
spectacular, but it has power-handling issues.
Is any mosfet comparable to the Cree C2M0280120D?
I've pushed that one to the limit.
That's my favorite one, that I was talking about.
But its 0.6-ohm Ron (when hot) is rather high, and
its weak 62W case rating is rather low. Also, it
comes in a wastefully-huge TO-247 package. But,
hey, it's not expensive, and makes great pulses.
The chip is tiny for the package.
https://www.dropbox.com/s/hnu2b7qlfw98bwq/Cree_Chip.JPG?dl=0
Its RDS-on tempco is awful, close to thermal runaway turf. There's a
similar ST fet that has a much flatter Rds tempco.
The wide bandgap parts blow aray silicon MOSFETs at HIGH(er) voltages.
At low voltage, say, 100V and below, silicon have much lower RdsOn,
bigger die (important for surge current) and low enough voltage that
the shitty diode reverse recovery time isn't much of an issue.
And the price is always higher at the moment for the same size die of
SiC than it is for Si. Hopefully that will change someday soon.
SiC is awesome stuff though. I use both SiC and Si.
The substrate diode in the Cree is awful, slow turn-on. The Spice
model lies about that.
Really ? I think I saw you or someone else say that. I have some
Cree SiC FETs now that I am going to try in place of the ROHM parts
that are already working awesome. They are cheaper than the Rohm's
but also have a smaller die I believe.
The Cree parts have nice low gate series resistance, so they switch
wicked fast... if you can drive the gates hard enough. A bit of series
inductance really helps. Some other SiC parts have absurd gate
resistances.
The next generations of Rohm SiC FETs have MUCH lower gate resistance.
10 or 20 times less and lower gate charge as well. Smaller die for
the same RdsOn but that's OK because we'd be using a lower RdsOn part
anyway, which has a better short current time spec.
The frequencies that I am running these things at, whcih is less than
50 kHz at the moment, is fairly easy. The newer generations require
less gate voltage for full turn on as well. Same with the
Cree/Wolfspeed parts. 15V recommended rather than 20V.
I also use negative drive when possible but SiC parts are kind of
picky and don't want to exceed their ratings for long life.
Silicon, for hard switching HV power is unusable for me.
I have been all hot for GaN parts since about 2005 but still, there
aren't any parts I can use for several hundred volts like there are
for SiC FETs.
We are having good luck with the EPC BGA GaN parts as super fast
switches. Pain to assemble, but electrically great. Unlike SiC, they
are happy with 4 or 5 volts of gate drive.
https://www.dropbox.com/s/k1k4i1r2nhuhnyk/T577_40V_Pulse.jpg?raw=1
(40 volt supply, 50r out, loaded to make 20 volts)
Gotta find a use for that circuit.
Would be Interested to see the drive circuit for that.
That's kinda private. But regular cmos logic chips can drive low-side
GaN fets. ACT maybe. All three sections of NL37WZ16US in parallel is
awesome.
The high-side driver in a GaN totem pole is harder.
On Tue, 18 Jun 2019 23:21:56 -0700 (PDT), whit3rd <whit3rd@gmail.com
wrote:
On Tuesday, June 18, 2019 at 4:33:28 PM UTC-7, boB wrote:
Silicon, for hard switching HV power is unusable for me.
Well, except maybe for big thyristors; a full 8-inch wafer
2kV 4kA switch would be hard to replace in SiC.
Still, thyristor turnoffs aren't a pleasant subject, and
the old horizontal output transistors were TERRIBLE
switches at HV (but they could tolerate the HV
after switching OFF at a moderate voltage).
The c-b junctions of some horizontal output transistors made fabulous
Grehkov (drift step-recovery) diodes. I miss them.
Here's a negative 2KV pulse that was used in a tomographic atom probe.
https://www.dropbox.com/s/cus0eoleswyi444/T222_2KV_Pulse.JPG?raw=1
https://www.dropbox.com/s/87kx36pv8onh3t5/T222_Neon2.jpg?raw=1
I applied +80 volts to the junction in the forward direction and
waited a while for it to conduct, maybe 100 amps. Then reversed biased
it 400 volts through an inductor. When it snapped off, it made a big
spike.
On 18 Jun 2019, boB <boB@K7IQ.com> wrote:
On 18 Jun 2019, John Larkin wrote:
We are having good luck with the EPC BGA GaN parts as
super fast switches. Pain to assemble, but electrically
great. Unlike SiC, they are happy with 4 or 5 volts
of gate drive.
https://www.dropbox.com/s/k1k4i1r2nhuhnyk/T577_40V_Pulse.jpg?raw=1
(40 volt supply, 50r out, loaded to make 20 volts)
Gotta find a use for that circuit.
Would be Interested to see the drive circuit for that.
That's kinda private. ...