Hacking a depletion MOSFET model

[snip]

I posted an easy-to-read Level=3 description a while back, but now can't find it ;-)

I'll poke around and repost when I do... it's was essentially just three lines. ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
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     Thinking outside the box... producing elegant solutions, 
              by understanding what nature is hiding. 

"It is not in doing what you like, but in liking what you do that 
is the secret of happiness."  -James Barrie

Change W to 400 microns, everything is proportional to W/L.

Am 14.07.2018 um 01:00 schrieb Jim Thompson:

I happened to search a depletion fet as a cascode/bootstrap for my IF3602s at elevated current and it was rainy yesterday, so here they are:

Microchip LND150, Mouser, half a year old: <

>

Microchip DN2470 <

> I have no idea where this limit comes from. Could be that chinese el cheapo curve tracer. Its documentation is, OMG! What documentation? It was repeatable, but does not happen at larger VDD.

IXYS CPC3902 <

>

ixys_cpc3703 <

>

Microchip DN3525 <

>

Microchip dn3525 (left) and Infineon bsp149 (right) <

>

All but the LND150 came from DK last week.

cheers, Gerhard

Am 16.07.2018 um 17:18 schrieb Gerhard Hoffmann:

Forgot Infineon BSS159 SOT-23

< >

Hi Gerhard, Can you take a minute to tell me what is being plotted here. The bottom (x) axis looks to be gate-source voltage. Is the vertical (y) axis the drain current? (And if so why doesn't it go to zero?)

Thanks George H.

Yes, Id over Vgs. And the Chinese curve tracer has its problems with offset / precision. We did a lot better @ Verigy :-)

OK thanks, I figure I can hack up a curve tracer in two ways; A voltage source into a TIA, current to voltage converter, Or a current source into a voltage sensor('scope).

Then add some button(s) to take off the offsets.

(I like the function generator into TIA, 'cause I sorta know TIA's from photodiodes.)

George H.

Watch dissipation, use low repetition rate.