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MOSFET hfe Beta current gain.

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Harry D

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Oct 31, 2014, 1:19:26 PM10/31/14
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Attached MOSFET device with a nice hfe of 95, who knew?

http://www.genesicsemi.com/images/products_sic/sjt/GA50JT17-247.pdf

Enjoy, Harry

Jim Thompson

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Oct 31, 2014, 1:32:23 PM10/31/14
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On Fri, 31 Oct 2014 10:19:20 -0700, "Harry D" <har...@tdsystems.org>
wrote:

>Attached MOSFET device with a nice hfe of 95, who knew?
>
>http://www.genesicsemi.com/images/products_sic/sjt/GA50JT17-247.pdf
>
>Enjoy, Harry

You're letting the symbol confuse you. It's not an IGBT, it's a
BJT-current-driven-into-channel MOS device, whatever you might call
that ;-)

...Jim Thompson
--
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| San Tan Valley, AZ 85142 Skype: skypeanalog | |
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I love to cook with wine. Sometimes I even put it in the food.

Glenn

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Oct 31, 2014, 2:00:32 PM10/31/14
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I vote that it is a some "bastard" J-FET, that have the PN-gate forward
biased?:

"Gate Oxide Free SiC Switch"

"Compatible with Si MOSFET/IGBT Gate Drive ICs"

"Gate On Voltage VGSON" 3,5V figure 4 (actually figure 7)

Glenn

Glenn

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Oct 31, 2014, 2:08:19 PM10/31/14
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Here it is called a:

GeneSiC Releases 25 mOhm/1700 V Silicon Carbide Transistors:
http://www.pr.com/press-release/589198
Quote: "...
SiC Junction Transistors (SJT)
..."

Glenn

Jim Thompson

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Oct 31, 2014, 2:30:28 PM10/31/14
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On Fri, 31 Oct 2014 10:32:19 -0700, Jim Thompson
<To-Email-Use-Th...@On-My-Web-Site.com> wrote:

>On Fri, 31 Oct 2014 10:19:20 -0700, "Harry D" <har...@tdsystems.org>
>wrote:
>
>>Attached MOSFET device with a nice hfe of 95, who knew?
>>
>>http://www.genesicsemi.com/images/products_sic/sjt/GA50JT17-247.pdf
>>
>>Enjoy, Harry
>
>You're letting the symbol confuse you. It's not an IGBT, it's a
>BJT-current-driven-into-channel MOS device, whatever you might call
>that ;-)
>
> ...Jim Thompson

After some more pondering I realize it's a giant _lateral_ NPN, which
gets the voltage wa-a-a-ay up.

(Lateral PNP's on my custom microchips typically have breakdown
voltages in excess of 30V, on an otherwise 5V process.)

John Larkin

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Oct 31, 2014, 4:08:55 PM10/31/14
to
On Fri, 31 Oct 2014 10:19:20 -0700, "Harry D" <har...@tdsystems.org>
wrote:

>Attached MOSFET device with a nice hfe of 95, who knew?
>
>http://www.genesicsemi.com/images/products_sic/sjt/GA50JT17-247.pdf
>
>Enjoy, Harry

Cool, an SiC bipolar transistor.

I've seen a strange effect in phemts, both depletion and enhancement
mode devices. As you raise the gate voltage, the drain currrent goes
way up as the gate begins to draw current, around +0.6 volts or so,
almost a bipolar effect on top of the usual jfet-like behavior.


--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

Tim Williams

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Oct 31, 2014, 8:04:15 PM10/31/14
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After all, JFETs are nothing more than UJTs with a very thin active
channel area (so the gate causes cutoff) and a short channel length (so
the conductivity modulation is generally small).

I haven't been able to observe much if any effect with generic silicon
JFETs, but perhaps the structure of PHEMTs does something. The channel is
a thin 2DEG, it might be the conductivity modulation affects the entire
bulk and massively increases conductivity.

Tim

--
Seven Transistor Labs
Electrical Engineering Consultation
Website: http://seventransistorlabs.com

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