Optical Attenuator/switches... any one ever even seen these. Opto isolated FETs

Mooly · 06:34 AM

With all the recent threads on attenuators and the "lightspeed" etc, wondered if anyone had ever come across this type of device.

First saw these in Elektor around 25 years ago (in an AGC circuit) and never seen the devices since.
http://www.nteinc.com/specs/3000to3099/pdf/nte3085.pdf

Wonder how they could be made to perform... noise/tracking etc. 100ohm to 300meg ohms is the quoted range of "resistance"

Nrik · 22nd May 2010, 08:08 AM

That surely looks nice :-)

sakis · 22nd May 2010, 08:31 AM

hei mooly ...ever had in your life an nte thing that works properly ??? ...

gfle · 22nd May 2010, 08:44 AM

IS610 is the original part.
http://pdfdata.datasheetsite.com/web/59082/IS610.pdf

Mooly · 22nd May 2010, 10:44 AM

Quote:

Originally Posted by sakis

hei mooly ...ever had in your life an nte thing that works properly ??? ...

can't recall having come across the NTE brand before for DIY parts... might have some old germaniums marked NTE, not sure.

You had bad experience ?

Mooly · 22nd May 2010, 10:45 AM

Quote:

Originally Posted by gfle

IS610 is the original part.
http://pdfdata.datasheetsite.com/web/59082/IS610.pdf

Thanks for the link... keep thinking back to the old Elektor mag (summer circuits ?). Was it a dual or quad device even. Wish I had kept a lot of the old mags now.

krachkiste · 22nd May 2010, 11:54 AM

I'm not sure if I fully understand your question.
Do you mean, specifically come accros this NTE thing? No.
But I've used the panasonic photomos switches, which are optically isolated FETs.

CBS240 · 22nd May 2010, 02:29 PM

I like the IL300 from Vishay. It has two matched photodiodes so that one of them can be used to servo the LED in order to linearize its characteristics. Great BW too.

I have played with it in both photoconductive and photovoltaic mode. I use a couple of them in my latest amp circuit in photoconductive but only for DC bias control, not for signal coupling. I wonder if it would be possible to use one in place of the input cap? I am seriously considering giving it a try. One thing I hate in SS amps is coupling capacitors of any kind. The input cap is a requirement but if I can replace it with one of these linearized opto-couplers it would be cool.

Hmm, maybe I should test it as an input coupler and see how it sounds first.

poopydoopynoopy · 22nd May 2010, 03:37 PM

nielsen media research used to use those for metering video game switches and other devices...

Mooly · 22nd May 2010, 04:05 PM

Some interesting devices out there for sure. The IL300 is another new one to me... thanks CBS240

krashkiste... The photomos relays are interesting... I remembered this thread a while back, have a look at post #6

MosFet Relais

Any photomos ones high enough rated for this application i wonder.

It's good to see what's "out there"... you never know when you have an idea that can use it.

22nd May 2010, 06:32 AM	#1
Mooly diyAudio Member Join Date: Sep 2007	Optical Attenuator/switches... any one ever even seen these. Opto isolated FETs With all the recent threads on attenuators and the "lightspeed" etc, wondered if anyone had ever come across this type of device. First saw these in Elektor around 25 years ago (in an AGC circuit) and never seen the devices since. http://www.nteinc.com/specs/3000to3099/pdf/nte3085.pdf Wonder how they could be made to perform... noise/tracking etc. 100ohm to 300meg ohms is the quoted range of "resistance" __________________ ------------------------------------------------------- *A simulation free zone.* *Design it, build it, test it.* Last edited by Mooly; 22nd May 2010 at 06:34 AM.

22nd May 2010, 08:08 AM	#2
Nrik diyAudio Member Join Date: Feb 2005 Location: Copenhagen	That surely looks nice :-) __________________ STOP - Hammertime!

22nd May 2010, 08:31 AM	#3
sakis diyAudio Member Join Date: Jan 2006 Location: nea makri athens greece	hei mooly ...ever had in your life an nte thing that works properly ??? ... __________________ SERVICE ΙΑΠΩΝΙΚΩΝ ΜΗΧΑΝΗΜΑΤΩΝ ΗΧΟΥ www.eastelectronics.gr

22nd May 2010, 02:29 PM	#8
CBS240 diyAudio Member Join Date: Aug 2005 Location: K-town	I like the IL300 from Vishay. It has two matched photodiodes so that one of them can be used to servo the LED in order to linearize its characteristics. Great BW too. I have played with it in both photoconductive and photovoltaic mode. I use a couple of them in my latest amp circuit in photoconductive but only for DC bias control, not for signal coupling. I wonder if it would be possible to use one in place of the input cap? I am seriously considering giving it a try. One thing I hate in SS amps is coupling capacitors of any kind. The input cap is a requirement but if I can replace it with one of these linearized opto-couplers it would be cool. Hmm, maybe I should test it as an input coupler and see how it sounds first. __________________ All the trouble I've ever been in started out as fun......

22nd May 2010, 04:05 PM	#10
Mooly diyAudio Member Join Date: Sep 2007	Some interesting devices out there for sure. The IL300 is another new one to me... thanks CBS240 krashkiste... The photomos relays are interesting... I remembered this thread a while back, have a look at post #6 MosFet Relais Any photomos ones high enough rated for this application i wonder. It's good to see what's "out there"... you never know when you have an idea that can use it. __________________ ------------------------------------------------------- *A simulation free zone.* *Design it, build it, test it.*


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22nd May 2010, 08:44 AM	#4
gfle diyAudio Member Join Date: Mar 2001 Location: Athens, GREECE	IS610 is the original part. http://pdfdata.datasheetsite.com/web/59082/IS610.pdf

22nd May 2010, 11:54 AM	#7
krachkiste diyAudio Member Join Date: May 2009	I'm not sure if I fully understand your question. Do you mean, specifically come accros this NTE thing? No. But I've used the panasonic photomos switches, which are optically isolated FETs.

22nd May 2010, 03:37 PM	#9
poopydoopynoopy diyAudio Member Join Date: Oct 2008 Location: 97220	nielsen media research used to use those for metering video game switches and other devices...

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