On Semi ThermalTrak

davidallancole · 11th January 2006, 09:17 PM

Has anybody tried the new ThermalTrak transistors from On Semiconductors? They have a diode for biasing built right into the package.

Stocker · 11th January 2006, 11:20 PM

I was going to tell you to search, but then I did it and nobody had used them yet and reported back about it. I did find one interesting application note where the temperature monitoring was done with the inbuilt diodes in series on paralleled transistors, but that's about it.

somebody actually HAD some of these, but didn't report back what they did with them...?

DoomPixie · 11th January 2006, 11:22 PM

why not get some and have a play around uourself and see what you can get out of them? or are they stupidly expensive? they sound pretty cool though..

Owen

davidallancole · 11th January 2006, 11:36 PM

They kind of are expensive. About $10 a piece from Digikey. Plus I don't have any equipment yet for building amps.

DoomPixie · 11th January 2006, 11:43 PM

fair enough, they are pretty expencive. They do sound pretty cool though, hopefully someone out there has played around with them, i will be keeping an eye on this thread, could turn out to be quite interesting.
Owen

Leolabs · 11th January 2006, 11:50 PM

Sanken does manufacture those kind of transistors,should be nothing special.

davidallancole · 11th January 2006, 11:54 PM

Heres an apllication note on using these in a power amplifier.

http://www.onsemi.com/pub/Collateral/AND8196-D.PDF

lineup · 11th January 2006, 11:58 PM

Interesting devices!

Diode that senses the temperature, like a transistor in a VBE multiplier,
has its own 2 pins.
So the ThermalTrak is a 5 pins device.
See attached image.
----------------------

Complementary ThermalTrak™ Transistors
NJL3281D(NPN) NJL1302D(PNP)
BIPOLAR POWER TRANSISTORS
TO-264, 0.625 °C/W
15 A, 260 V, 200 W
fT 30 MHz

http://www.onsemi.com/PowerSolutions...do?id=NJL1302D

clem_o · 12th January 2006, 12:02 AM

Unfortunately they don't seem to be optioned for free sampling.

I wonder how well they match off with standard MJL3281/1302? Since most amplifier designers will go with a VBE multiplier (and perhaps use several output transistors in parallel), maybe it will be viable to get just one NJL device, use its thermal diode for bias tracking, and use standard MJL stuff for the rest - cost savings, assuming these transistors are reasonably matched...

Cheers!

Clem

anatech · 12th January 2006, 02:03 AM

Hi Clem,
Good thought for a manufacturer who wants to mystify the average service person. It adds a skew to the inventory and may become unavailable. Standard methods are reliable and so most manufacturers will be reluctant to use them.

If it's needed to track temperature that closely in an amplifier, I feel it's a marginal design.

Now if a replacement from NTE shows up ... Sad state of affairs for many repair shops.

-Chris

11th January 2006, 09:17 PM	#1
davidallancole diyAudio Member Join Date: Nov 2005	On Semi ThermalTrak Has anybody tried the new ThermalTrak transistors from On Semiconductors? They have a diode for biasing built right into the package.

11th January 2006, 11:20 PM	#2
Stocker diyAudio Member Join Date: Dec 2003 Location: Austin	I was going to tell you to search, but then I did it and nobody had used them yet and reported back about it. I did find one interesting application note where the temperature monitoring was done with the inbuilt diodes in series on paralleled transistors, but that's about it. somebody actually HAD some of these, but didn't report back what they did with them...? __________________ Jesus loves you.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
my project: class B with ThermalTrak	mafoe	Solid State	37	16th June 2009 04:30 PM
ThermalTrak transistor application.	Jeb-D.	Tubes / Valves	37	9th May 2009 02:17 AM
OnSemi ThermalTrak	Arius	Solid State	8	26th August 2005 04:09 PM
ThermalTrak circuit design	Mambo	Solid State	4	12th July 2005 11:03 AM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

11th January 2006, 11:22 PM	#3
DoomPixie diyAudio Member Join Date: Jun 2005 Location: Aberystwyth / Llanelli (wales)	why not get some and have a play around uourself and see what you can get out of them? or are they stupidly expensive? they sound pretty cool though.. Owen

11th January 2006, 11:36 PM	#4
davidallancole diyAudio Member Join Date: Nov 2005	They kind of are expensive. About $10 a piece from Digikey. Plus I don't have any equipment yet for building amps.

11th January 2006, 11:43 PM	#5
DoomPixie diyAudio Member Join Date: Jun 2005 Location: Aberystwyth / Llanelli (wales)	fair enough, they are pretty expencive. They do sound pretty cool though, hopefully someone out there has played around with them, i will be keeping an eye on this thread, could turn out to be quite interesting. Owen

11th January 2006, 11:50 PM	#6
Leolabs diyAudio Member Join Date: Dec 2004 Location: Bukit Mertajam	Sanken does manufacture those kind of transistors,should be nothing special.

11th January 2006, 11:54 PM	#7
davidallancole diyAudio Member Join Date: Nov 2005	Heres an apllication note on using these in a power amplifier. http://www.onsemi.com/pub/Collateral/AND8196-D.PDF

12th January 2006, 12:02 AM	#9
clem_o diyAudio Member Join Date: Jun 2005 Location: Manila	Unfortunately they don't seem to be optioned for free sampling. I wonder how well they match off with standard MJL3281/1302? Since most amplifier designers will go with a VBE multiplier (and perhaps use several output transistors in parallel), maybe it will be viable to get just one NJL device, use its thermal diode for bias tracking, and use standard MJL stuff for the rest - cost savings, assuming these transistors are reasonably matched... Cheers! Clem

12th January 2006, 02:03 AM	#10
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi Clem, Good thought for a manufacturer who wants to mystify the average service person. It adds a skew to the inventory and may become unavailable. Standard methods are reliable and so most manufacturers will be reluctant to use them. If it's needed to track temperature that closely in an amplifier, I feel it's a marginal design. Now if a replacement from NTE shows up ... Sad state of affairs for many repair shops. -Chris