Matching IRFP244 MOS-FETs - Page 4 - diyAudio
Go Back   Home > Forums > Amplifiers > Pass Labs

Pass Labs This forum is dedicated to Pass Labs discussion.

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 5th June 2011, 06:44 AM   #31
diyAudio Member
 
Bksabath's Avatar
 
Join Date: Dec 2007
Went trough most of this before hope it may helps.

Frags posted a couple of SCH for differential testing in 9 December
Tanks again to Frags for ideas and help.
The 2 first pictures are his original work.


I have made up a little test rig with a CPU fan and a simple controller.
Just parts I had already and quite suprised on how well it works
may be handy as fan speed contreller later on.

It can dissipate well over 50W (done my matching at 26V and 2A) and keep temperature whiten + - 1 C of the 50 C I picked out of the hat.

While I measure one duda the next few are sitting on the plate getting worm.

I get Vgs to settle in a minute or so and at 50 C the effect of ambient temperature and air currents is greatly reduced.

Maybe at 30 C one may risk corrupting results Just by touching the little Bug...

QSP is doing same much more advanced testing and he posted a SCH for Tran conductance matching.

Although next on my list of to do things I have not tried that one out
But well worth a look at (just search for QSP posts as at the moment I have lost it)

Holco MFR 15ppm 2W for sale
Attached Images
File Type: jpg FRAG912diff_test.JPG (35.8 KB, 116 views)
File Type: jpg Frags912 2test2.jpg (37.3 KB, 118 views)
File Type: jpg MATCHING TEST RIG 001.jpg (593.5 KB, 101 views)
File Type: jpg MATCHING TEST RIG 002.jpg (620.3 KB, 96 views)
File Type: jpg MATCHING TEST RIG 003.jpg (622.8 KB, 91 views)
  Reply With Quote
Old 5th June 2011, 07:19 AM   #32
Banned
 
Join Date: Nov 2006
Location: Torpoint
Vgs is better generated with a stabilized voltage. I used an LM317.

Using the LM317 I was able to match sextets out of a batch of 50 to within 2% of each other.
  Reply With Quote
Old 6th June 2011, 11:22 AM   #33
Banned
 
Join Date: Nov 2006
Location: Torpoint
After the matching process I now have 26 x IRFP244s left over.

These have all gone through the matching process and will be supplied with the relevant data to enable you to pick out matched pairs and triplets.

50.00 the lot plus P&P.

Last edited by Andy5112405; 6th June 2011 at 11:30 AM.
  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
MOS-FETS exclusively, input to output, why Nelson? Jazzo Pass Labs 10 29th November 2007 03:53 AM
matching FETs and found leaking? bigpanda Parts 1 24th August 2006 06:44 AM
MOS-FET matching Skorpio Pass Labs 16 30th November 2005 10:33 AM
MOS FETs, BJTs or both? DarkOne Solid State 4 5th October 2001 01:14 AM


New To Site? Need Help?

All times are GMT. The time now is 06:01 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