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-   -   Replacement for 10M45 / CCS (http://www.diyaudio.com/forums/power-supplies/221058-replacement-10m45-ccs.html)

hugenh 6th October 2012 07:13 PM

Replacement for 10M45 / CCS
 
Hi,
is there an alternative for this IC since i have trouble locating an european distributor?

To built i it with discrete elements would be fine for me, too :)

Salas 6th October 2012 07:49 PM

Its no true IC, just a depletion mode MOSFET that you can set its IDSS just like a JFET. Supertex DN2540 is analogous, bit better spec actually.

hugenh 13th October 2012 09:42 AM

hmm, same problem. hard to source for me here in norway. please, could anybody boint me to some reading about this kind of CCS?

seems that a lot of power MOSFET-types could work, but the datasheets are full of slightly divergent characteristics, so i don`t know what to look after.

thanks for any input, harry

Salas 13th October 2012 10:48 AM

Ebay is full but a bit of a rip off pricing there.

"Sources 101, Part 2", page 3.
Services

roger57 12th November 2012 04:01 AM

How does this CCS Operate?
 
Hi,

Can anyone tell me (or redirect me to a better forum?) how this circuit operates? (the DN2540's in the cathodes of the E88CC LTP)

http://richardsears1.files.wordpress...pp-amp-sch.jpg

I'm at a loss to understand how the gates get enough drive voltage to enable the FETs. In LTSpice, I've tried it in the cathodes of a 6SN7 LTP and couldn't get it to work. Used the supertex.lib model.

GaryB 12th November 2012 04:11 AM

Quote:

Originally Posted by hugenh (Post 3192053)
Hi,
is there an alternative for this IC since i have trouble locating an european distributor?

To built i it with discrete elements would be fine for me, too :)

Have you looked here?
10M45 at Mouser

---Gary

jcx 12th November 2012 05:01 AM

normal enhancement mode MOSFET require added source of voltage for gate

Welcome to Gary Pimm's DIY Page shows a couple of ccs options

depletion mode MOSFET can work like JFET ccs with source R setting current but there are few part # made

roger57 12th November 2012 02:06 PM

Quote:

Originally Posted by jcx (Post 3238230)
normal enhancement mode MOSFET require added source of voltage for gate

Welcome to Gary Pimm's DIY Page shows a couple of ccs options

depletion mode MOSFET can work like JFET ccs with source R setting current but there are few part # made

Hi,

Thanks for your response. BTW - the DN2540 is a depletion mode mosfet. :eek:

However, has anyone actually looked at this schematic? There are no external connection points for gate drive. It doesn't appear that anything is required.
So I'm back to the question, will this circuit work, if not, what's needed to make it work? Has anyone successfully used this in a long tail pair? Has anyone successfully modeled this in LTSpice?

I'd be happy to plop this question in another forum if this one's not OK for this, and a moderator could tell me which one.

Thanks,
Gary

Salas 12th November 2012 03:49 PM

Works like a Jfet cascode cathodes sink ccs. The lower semi is in idss mode while the upper one provides vds to it by means of spanning it with its vgs.

jcx 12th November 2012 04:02 PM

N type (only type available for MOSFET) depletion mode devcies conduct Idss with Vgs=0, are progressively cutoff by Vgate lower than Vs

the Vgate "comes from" the current flowing in the R in series with the source - allows selecting an operating current that is < Idss

as pointed out this is the same as N jfet ccs, CRD

Quote:

Originally Posted by jcx (Post 2635947)
http://liveweb.archive.org/http://ww...0596/70596.pdf

those intersted will probably want all of the Siliconix app notes: JFETs Application notes



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