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flg 23rd October 2009 10:35 AM

IXYS depletion MOSFETs: What are they good for?
O.K. I think we've all seen the Depletion Mode MOSFET Zen Lite variant displayed by N.P. at BA'09. Personally, I did not know that part existed? But, it appears to have some quite conveniant qualities:
Suitable Voltage rating, Current rating, self biasing like the LU1014D, "Idss" of about 2.5A, Rthjc .31 C/W, plenty of S.O.A., fairly linear C in our typical operating range, and by all accounts so far, fairly linear and good sounding. Oh yea, affordable price in small enough orders. Did I miss something?
I'm not so interested in another Zen Lite but as I've seen recently, I'm not the only one interested in creating a monster B1 circuit. I was thinking of paralelled LU1014Ds with car battery rails. This device can take that idea further and easier as Paul Hynes did a few years ago (someone posted an AudioCircle link around here somewhere). I've also played with the Circlotron circuit quite a bit and it's very nice but, with self biasing and ground refrenced input as Paul Hynes has already done also wow :)
Personally, I can't wait to play with this part. There is a GB thread started to research the interest in obtaining some.
So, I thought I'ld get us all started on a discussion for everyone's benifit. Oh, yea, another great quality, N.P. seems to like this part too...
Any other comments? questions? previous experiance? Ideas?

flg 25th October 2009 06:03 PM

2 Attachment(s)
Just a few examples of simplied circuits that could use these devices... I'm sure you recognize them :)

And the interesting thread regarding these parts by Paul Hynes from another forum :o

Two simple Current Amplifiers for low impedance loads

flg 25th October 2009 06:05 PM

1 Attachment(s)
I couldn't attach the third one :mad:
Here it is...

Nelson Pass 25th October 2009 07:06 PM

The part I used on the BAF example was the IXYS
IXTH20N50D which has about 1.25A current with a 0
Gate voltage.


flg 25th October 2009 07:42 PM

I don't mean to misslead anyone or anyhing but first I must say this: I've done some data sheet tests myself, mostly because my Boss always responds to my reasoning gathered from datasheets with "Data Sheets Lie".
Having said that, I realized recently that I have 2 copies of the datasheet for this device. One of them from 2006??? And the other is current on the IXYS website(2009). I may not have been thoughtfull enough with looking at them? or posting accurately.
I have one other peice of info I was going by. The Link I posted refrencing Paul Hynes work states that in his application, at his temps etc. he see's about 2.5A.
All in all, I think it's a very interesting part and I would not even know about it's existance without The One And Only sharing with us. Thanks Nelson.

Nelson Pass 26th October 2009 07:18 PM

I ran across it somewhere in this site, so of course I just
bought some.


Nevod 27th October 2009 06:13 AM

These circuits look tube-ish.. :) easy to understand.

djk 27th October 2009 07:21 AM

"I ran across it somewhere in this site, so of course I just
bought some."

I asked about them 5 May 2006 here (#16):

wrenchone 27th October 2009 08:00 AM

My intentions for this or a similar depletion MOSFET will be tubish, involving a transformer, 250V, and some JFET accomplices. Unlike tubes, a big, fat heat sink gets tossed in...

flg 28th October 2009 02:41 AM

Isn't there a somewhat popular, classic maybe, Zen-like amp that uses an output transformer and a MOSFET? I don't recall the name obviously but it has somewhat of a reputation?

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