New depletion MOSFET - BSS126

Weird. The LND150 is 500V, 1.6 mA, and looks like 1k for small signals.

13 of them in parallel would have about the same IDSS but only 1/4 of the zero-bias resistance.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC / Hobbs ElectroOptics 
Optics, Electro-optics, Photonics, Analog Electronics 
Briarcliff Manor NY 10510 

http://electrooptical.net 
http://hobbs-eo.com

Nice.

But Idss is 7 mA min, 25 typ (from the graphs), no max. And Id is 21 mA abs max! So it can't legally be used at Idss.

The Supertex parts are very repeatable in real life. I use a lot of LND250 and DN2530.

Depletions are good for all sorts of things. Like to discharge filter caps through an LED. The voltage declines linearly to near zero, where the LED winks out.

Nice for current limiters and making high-voltage regulators.

--

John Larkin         Highland Technology, Inc 

Science teaches us to doubt. 

  Claude Bernard

We use one DM NFET in a product I think. Normally On I like to call them.

We were talking about depeletion mode FETs the other day and I wondered why I could not find a P-Channel depletion mode FET ?

I don't think that anyone makes a P-chammel version ? Anybody know ? Not that I need one.... Just wondering

Nothing fundamental, they can be found in the ICs.

Best regards, Piotr

600V in SOT23, that is interesting.

Yes, they are cool.

Olaf

Only thing that's not reasonable to make AFAIK in a BICMOS process is a PNP power BJT, at least not if you want N-type devices on the same die since the substrate layer is usually P material, and not thick enough for both the buried collector p-type section and n-type isolation layer around it you'd need to handle high currents.

On Sunday, September 13, 2020 at 12:27:49 PM UTC-7, snipped-for-privacy@yahoo.com wr ote:

epletion-mode-mosfet/

(and I hope to join the fan club someday too)!

Cool. Thanks.

I used a couple BSS159N recently in a current source/limiter. For that app, any solutions that were not depletion were more complicated.

The thing about depletion is that you must do something to "turn it off" (s top it from conducting) whereas for enhancement (MOS) and bipolar, somethin g must be done to "turn it on." So, that "ON till you turn it OFF" is a spe cial characteristic not easily emulated by other devices.

Here are a few depl circuits:

(the last one uses a depletion-mode tube)

--

John Larkin         Highland Technology, Inc 

Science teaches us to doubt. 

  Claude Bernard