Can you give names?
I compared datasheet values for the Philips PH7030L, that we use in decent numbers, against recent parts with similar specs and SOA of the new parts was much smaller.
-- Uwe Bonnes bon@elektron.ikp.physik.tu-darmstadt.de Institut fuer Kernphysik Schlossgartenstrasse 9 64289 Darmstadt --------- Tel. 06151 1623569 ------- Fax. 06151 1623305 ---------
This (17 KW NMR gradient amplifier)
used IXTH11P50 and IRFPS37N50A. They were the survivors of our testing.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
John Larkin wrote in news: snipped-for-privacy@4ax.com:
Proper assembly of those would require bolting down all those devices AND the PCB assembly BEFORE hand soldering each lead on each of those thermal mounted packeges to insure perfect coplanarity.
I know because we had a similar design and bolting on the heat sink and it eements afterward is a guarantee that you are going to smoke one or more of them.
that or shape the leads so they can move a bit.
NT
snipped-for-privacy@gmail.com wrote in news:d4df6b83-cd10-4dc2-8653-aeacc7fd8d83 @googlegroups.com:
One canot "shape the leads" These devices are dependent on thermal conductivity to abate heat.
Bending copper die leads causes microfractures in the copper, as well as the packaging epoxy.
There should be no lead forming operations whatsoever with these types of devices.
Copper work hardens. And NO, not a single one is made to be able "to move a bit". These are SMT devices too. All the more reason to leave the leads the f*ck alone. We had long leaded thru hole units and we had to place bead inductors on one lead of each to enhance operation. They are a SLIGHT bit more mutable, but take care not to stress the copper where it enters the device body.
That has to be one of the more stupid 'solutions' I have ever seen made.
I deleted it after posting - at least according go goole - because my reply didn't go into nearly enough detail and as you point out is not suitable for sm stuff.
NT
I connect them both to a grounded DC voltage source, 60 volts to force the die temp to 60C for example. One or both of them actually output current, an amp per watt or something, so you can't float them or they go to megavolts and the die temp gets crazy.
The voltage and current of these pins are referenced to Spice ground. That completely screws up the alt/click thing that measures power dissipation, so you see negative kilowatts and silly stuff. I build my own power dissipation calculator off to the side.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
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