Nice item...

http://www.cree.com/products/power_1700V.asp

In article ,
Pieyed Piper g wrote:

Nice item...

http://www.cree.com/products/power_1700V.asp

Sold through Digikey, for all those hobbyists who like to build their
semiconductor cases at home?
--
I won't see Google Groups replies because I must filter them as spam

On Mon, 28 Jun 2010 21:29:28 -0700, Kevin McMurtrie
wrote:

In article ,
Pieyed Piper g wrote:

Nice item...

http://www.cree.com/products/power_1700V.asp

Sold through Digikey, for all those hobbyists who like to build their
semiconductor cases at home?

Cases? It is an HV rectifier.

SiC diodes don't make much sense to me. I guess when you need DC from a rather large Tesla coil, you don't have much choice, but geez, the things are excellent resistors past 1V. The surge current is only 5 times rated current -- these things are fragile!

I'm surprised they're only rated to 175C. SiC was supposed to herald a new age of high temperature power semiconductors or something. As I recall, 150-175C limits are due to package epoxy. They should passivate it with glass and alumina or something. Make that sucker run red hot!

I suppose most of these problems will go away when they manage to grow SiC without a high defect density and with better carrier mobility. I just wonder if they can.

Reminds me, has anyone tried making GaN schottkies? The stuff should have similar properties to SiC, but apparently it has high mobility (enough to make GaN FETs run in the GHz, anyway!). Even a PN junction diode might be handy.

Oh, and speaking of "fancy" semiconductors, what happens when you make an SiGe heterojunction diode? Can one be made to similar current and voltage specs, with less t_rr and Qr than a regular homojunction?

Tim

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms

"Kevin McMurtrie" wrote in message ...
In article ,
Pieyed Piper g wrote:

Nice item...

http://www.cree.com/products/power_1700V.asp

Sold through Digikey, for all those hobbyists who like to build their
semiconductor cases at home?
--
I won't see Google Groups replies because I must filter them as spam

On Tue, 29 Jun 2010 03:22:07 -0500, "Tim Williams"
wrote:

SiC diodes don't make much sense to me. I guess when you need DC from a rather large Tesla coil, you don't have much choice, but geez, the things are excellent resistors past 1V. The surge current is only 5 times rated current -- these things are fragile!

I'm surprised they're only rated to 175C. SiC was supposed to herald a new age of high temperature power semiconductors or something. As I recall, 150-175C limits are due to package epoxy. They should passivate it with glass and alumina or something. Make that sucker run red hot!

I've used the Infineon SiC schottkies in HV pulse apps, and they
worked great. Low C, no reverse recovery, lots of voltage. I think I
used the 600 volt parts, in series.


I suppose most of these problems will go away when they manage to grow SiC without a high defect density and with better carrier mobility. I just wonder if they can.

Reminds me, has anyone tried making GaN schottkies? The stuff should have similar properties to SiC, but apparently it has high mobility (enough to make GaN FETs run in the GHz, anyway!). Even a PN junction diode might be handy.

Several people make GaN fets, which are phenomenal. Their figure of
merit Gm/Cd is off the charts. They had some materials problems a
couple of years ago (we blew up $1000 worth of Nitronex parts one
afternoon) but I think they're OK now. The SiC fets are more like
tubes, needing huge gate swings to do anything useful.

There are some GaN schottkies coming out lately.



Oh, and speaking of "fancy" semiconductors, what happens when you make an SiGe heterojunction diode? Can one be made to similar current and voltage specs, with less t_rr and Qr than a regular homojunction?

I don't know of any SiGe diodes. There are some nice SiGe transistors
and mmics. EclipsPlus logic is SiGe and goes like a greased pig. An EP
gate has enough swing to switch a GaN transistor on/off, which could
be interesting.

Fun toys.

John

"Kevin McMurtrie" wrote in message
...
In article ,
Pieyed Piper g wrote:

Nice item...

http://www.cree.com/products/power_1700V.asp

Sold through Digikey, for all those hobbyists who like to build their
semiconductor cases at home?

Don't knock Digikey. They are exclusive distributor for several lines like
CUI. CUI will sell direct only for large volumes. I have several turnkey
board assembly houses that buy through Digikey (among others). Lastly, the
Arrow Electronics salesperson that calls on me once said that he often
checks out the digikey website since their own, well, just sucks.

Pretty impressive specs. Positive tempco is a definite plus and the reverse
recovery is almost nothing. Vf is an order of magnitude above Germanium but
is on par with IGBTs.

When I read Schott, was thinking Schott technical glasses...
http://www.us.schott.com/english/index.html

On Tue, 29 Jun 2010 10:10:52 -0400, "Oppie"
wrote:

"Kevin McMurtrie" wrote in message
.. .
In article ,
Pieyed Piper g wrote:

Nice item...

http://www.cree.com/products/power_1700V.asp

Sold through Digikey, for all those hobbyists who like to build their
semiconductor cases at home?

Don't knock Digikey. They are exclusive distributor for several lines like
CUI. CUI will sell direct only for large volumes. I have several turnkey
board assembly houses that buy through Digikey (among others). Lastly, the
Arrow Electronics salesperson that calls on me once said that he often
checks out the digikey website since their own, well, just sucks.

Pretty impressive specs. Positive tempco is a definite plus and the reverse
recovery is almost nothing. Vf is an order of magnitude above Germanium but
is on par with IGBTs.

When I read Schott, was thinking Schott technical glasses...
http://www.us.schott.com/english/index.html


Well, we schott that idea all to hell.

In article ,
Pieyed Piper g wrote:

On Mon, 28 Jun 2010 21:29:28 -0700, Kevin McMurtrie
wrote:

In article ,
Pieyed Piper g wrote:

Nice item...

http://www.cree.com/products/power_1700V.asp

Sold through Digikey, for all those hobbyists who like to build their
semiconductor cases at home?

Cases? It is an HV rectifier.

It's a naked slice of semiconductor chip. It's meant to be soldered to
a rigid metal tab on one side, hooked up with aluminum wire bonding on
the other, then sealed under a conforming coating.

I think that "call your nearest regional representative" has to be the
biggest sales turn-off ever but I found it amusing that Digikey became
the solution. I hope they get some Pyralux samples
--
I won't see Google Groups replies because I must filter them as spam

"John Larkin" wrote in message ...
Several people make GaN fets, which are phenomenal. Their figure of
merit Gm/Cd is off the charts. They had some materials problems a
couple of years ago (we blew up $1000 worth of Nitronex parts one
afternoon) but I think they're OK now. The SiC fets are more like
tubes, needing huge gate swings to do anything useful.

There are some GaN schottkies coming out lately.

Ever tried any GaN FETs diode-strapped?

Hmm, but don't they rate the gate for reverse bias only? That could be an expensive test.

Did Nitronex refund their bloopers?

I don't know of any SiGe diodes. There are some nice SiGe transistors
and mmics. EclipsPlus logic is SiGe and goes like a greased pig. An EP
gate has enough swing to switch a GaN transistor on/off, which could
be interesting.

Aha, you're quite fond of diode-strapping BJTs. The B-C junction is the heterojunction, right? That should make an interesting diode. Those things have to be rated for more than a few volts (Vcbo), so it should be a passable diode for signals at least.

Not at all useful, I'm sure. Well, then again, if it's almost as fast as an RF schottky, but you needed femtoamps leakage, you'd probably get it from one of these.

Tim

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms

On Tue, 29 Jun 2010 08:58:57 -0700, Kevin McMurtrie
wrote:

In article ,
Pieyed Piper g wrote:

On Mon, 28 Jun 2010 21:29:28 -0700, Kevin McMurtrie
wrote:

In article ,
Pieyed Piper g wrote:

Nice item...

http://www.cree.com/products/power_1700V.asp

Sold through Digikey, for all those hobbyists who like to build their
semiconductor cases at home?

Cases? It is an HV rectifier.

It's a naked slice of semiconductor chip. It's meant to be soldered to
a rigid metal tab on one side, hooked up with aluminum wire bonding on
the other, then sealed under a conforming coating.

I think that "call your nearest regional representative" has to be the
biggest sales turn-off ever but I found it amusing that Digikey became
the solution. I hope they get some Pyralux samples

That is why they call them SAMPLES, idiot.

NO, they are NOT meant to get a drop of conformal coating on them. They
are rated at 1700V. They MUST be hard potted

Tim Williams wrote:
SiC diodes don't make much sense to me. I guess when you need DC from a rather large Tesla coil, you don't have much choice, but geez, the things are excellent resistors past 1V. The surge current is only 5 times rated current -- these things are fragile!

I'm surprised they're only rated to 175C. SiC was supposed to herald a new age of high temperature power semiconductors or something. As I recall, 150-175C limits are due to package epoxy. They should passivate it with glass and alumina or something. Make that sucker run red hot!

I suppose most of these problems will go away when they manage to grow SiC without a high defect density and with better carrier mobility. I just wonder if they can.

Reminds me, has anyone tried making GaN schottkies? The stuff should have similar properties to SiC, but apparently it has high mobility (enough to make GaN FETs run in the GHz, anyway!). Even a PN junction diode might be handy.

Oh, and speaking of "fancy" semiconductors, what happens when you make an SiGe heterojunction diode? Can one be made to similar current and voltage specs, with less t_rr and Qr than a regular homojunction?

Tim

175C?
You have got to be kidding.
I make shunt regulators and GUARANTEE full operation at specs to 200C!
I do 100 percent testing at 25C and 185C.
Only problems seen were due to poor reflow (about 1 in 200).

On Tue, 29 Jun 2010 11:59:14 -0500, "Tim Williams"
wrote:

"John Larkin" wrote in message ...
Several people make GaN fets, which are phenomenal. Their figure of
merit Gm/Cd is off the charts. They had some materials problems a
couple of years ago (we blew up $1000 worth of Nitronex parts one
afternoon) but I think they're OK now. The SiC fets are more like
tubes, needing huge gate swings to do anything useful.

There are some GaN schottkies coming out lately.

Ever tried any GaN FETs diode-strapped?

You mean like a PAD-1 jfet diode? That's probably not very useful, as
the gate metalization is delicate.



Hmm, but don't they rate the gate for reverse bias only? That could be an expensive test.

Did Nitronex refund their bloopers?

I don't know of any SiGe diodes. There are some nice SiGe transistors
and mmics. EclipsPlus logic is SiGe and goes like a greased pig. An EP
gate has enough swing to switch a GaN transistor on/off, which could
be interesting.

Aha, you're quite fond of diode-strapping BJTs.

I sometimes use the c-b junctions as super low-leakage diodes.

The B-C junction is the heterojunction, right?

I think so.

That should make an interesting diode. Those things have to be rated for more than a few volts (Vcbo), so it should be a passable diode for signals at least.

The SiGe transistors are low voltage devices. It would be interesting,
but as a practical matter schottky diodes are good, low c, and fast.


Not at all useful, I'm sure. Well, then again, if it's almost as fast as an RF schottky, but you needed femtoamps leakage, you'd probably get it from one of these.

BFT25 microwave transistor c-b junctions are astounding diodes. A few
tenths of a pF and tens of fA leakage.

LEDs are claimed to be pretty good too, in the dark. Capacitance is
high, though, 10-100 pF range.

Central Semi makes some really good multiple diodes, too, tens of fA.

John