OnSemi ThermalTrak - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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
Reply
 
Thread Tools Search this Thread
Old 23rd August 2005, 06:29 PM   #1
Arius is offline Arius  United States
diyAudio Member
 
Join Date: Mar 2004
Location: California
Default OnSemi ThermalTrak

Anybody has any interest in using OnSemi's ThermalTrak devices as the output devices in a Leach-clone?

They are not necessary the best method for biasing an output stage as evidenced by D.Self's work (Chapter Output Stage I) but I'd like to experiment with them. Besides, OnSemi claims measurable improvement.

If there is interest, then we can discuss them here. If not, I can proceed with trying them out and reporting in later. Got the parts in hand, so it'll be wasteful to not try them out.

http://www.onsemi.com/pub/Collateral/NJL3281D.PDF
http://www.onsemi.com/pub/Collateral/NJL3281D.PDF
http://www.onsemi.com/pub/Collateral/AND8196-D.PDF

One immediate question I have is whether to use a modified Vbe bias circuit (as per Leach) or use the internal diodes directly and forgo adjustment capability.

Thanks for looking.
Attached Images
File Type: jpg thermaltrak_s.jpg (27.5 KB, 499 views)
  Reply With Quote
Old 23rd August 2005, 06:46 PM   #2
dimitri is offline dimitri  United States
diyAudio Member
 
dimitri's Avatar
 
Join Date: Oct 2002
Location: retired
Send a message via ICQ to dimitri
where have you got them, lucky man?
i'm waiting for my samples for 6 months...
  Reply With Quote
Old 23rd August 2005, 08:03 PM   #3
Arius is offline Arius  United States
diyAudio Member
 
Join Date: Mar 2004
Location: California
I was surprised myself at how fast OnSemi was. I ordered them last Friday and they came in today from Arizona.

I really didn't expect them to send any because I truthfully told them my sample request was for lab use, not production product.

Well I suppose it helps if you are currently an OnSemi customer, which I am. Hopefully you'll get yours soon.
  Reply With Quote
Old 23rd August 2005, 10:03 PM   #4
dimitri is offline dimitri  United States
diyAudio Member
 
dimitri's Avatar
 
Join Date: Oct 2002
Location: retired
Send a message via ICQ to dimitri
thank you, ordered them for the second time

Quote:
or use the internal diodes directly and forget adjustment capability
pls, allow me a week and I'll compare diode and base-emitter junction current-voltage curves
  Reply With Quote
Old 24th August 2005, 03:35 PM   #5
Arius is offline Arius  United States
diyAudio Member
 
Join Date: Mar 2004
Location: California
Well, a quick exercise with the simulator shows a few possibilities. Think I'll use a modified VBE amplifier bias generator with the 6 diodes (3 output pairs) in the base-collector leg. Now all I need to do is try it out to see how well it tracks.
Attached Images
File Type: jpg 6diode_vq_s.jpg (21.0 KB, 364 views)
  Reply With Quote
Old 26th August 2005, 09:05 AM   #6
diyAudio Member
 
panson_hk's Avatar
 
Join Date: Aug 2005
Blog Entries: 10
i saw these parts first time in CES2005. Really want to try them (available fom Digikey).
  Reply With Quote
Old 26th August 2005, 02:42 PM   #7
diyAudio Member
 
Join Date: Aug 2005
Quote:
I was surprised myself at how fast OnSemi was. I ordered them last Friday and they came in today from Arizona.
This is because the parts come from Digi-Key, next day air. Motorola has arrangements with Digi-Key to ship most of their samples from there.

I hope to God Motorola does very well financially, otherwise they may stop doing this.
  Reply With Quote
Old 26th August 2005, 03:05 PM   #8
Mr Evil is offline Mr Evil  United Kingdom
diyAudio Member
 
Join Date: Aug 2004
Location: Behind you
Quote:
Originally posted by telewatt
...I hope to God Motorola does very well financially, otherwise they may stop doing this.
You do subsequently buy their products if the samples prove to be good don't you? Of course if people were only ordering samples out of greed then they would probably have to stop eventually, but none of us are like that, are we?
__________________
https://mrevil.asvachin.eu/
  Reply With Quote
Old 26th August 2005, 04:09 PM   #9
Arius is offline Arius  United States
diyAudio Member
 
Join Date: Mar 2004
Location: California
Well, I use OnSemi parts at work and I can say that their sample service is never that fast (unless it's a part from their preferred 24hr program).

Many times, the parts come out of Asia. Even parts from within the US have about a one week turn.

Anyhoo, you're right. Digikey stocks them now and they're about the same as the regular MJL parts in price.

About using the thermal traks themselves, I was thinking of using them (their internal diodes that is) in a modified VBE multiplier, except for one device. That last device will be the temp sensor for the protection circuit. That means one output stage junction will be uncompensated. Assuming equal current sharing, I think that'll be ok. Comments, anyone?
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
On Semi ThermalTrak davidallancole Solid State 639 1st May 2013 02:29 AM
ThermalTrak transistor application. Jeb-D. Tubes / Valves 37 9th May 2009 02:17 AM
Practical use of ThermalTrak diodes ceharden Solid State 5 9th April 2009 06:00 PM
onsemi "thermaltrak" transistors gmarsh Solid State 14 17th May 2005 12:16 PM


New To Site? Need Help?

All times are GMT. The time now is 06:23 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2