Class-E Totem-Pole Drive Documentation

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Postby frank carcia » Sat Jan 22, 2005 9:37 pm

I like your approach and will consider it for the 75 meter final.
The 160 rig is built so I will just add another stage of predriver
to drive the second driver stage/final. The parts I'm using run warm above 3 MHz, I have just enough room on the driver heat sink to add
a 4 FET push pull stage between both driver stages. I have some MIL
4423s that may work better. I think there are 1 amp parts in there now.
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Postby KM5TZ/6 » Sat Jan 22, 2005 11:35 pm

Tom WA3KLR wrote:Hi Dave,

I learned of the Maxim 4420 family but then for what was readily available at the time, the Microchip TC4420 family appeared to be another source. I don’t know who is the second source of who on these parts. I ordered some Microchip TC4429CPA’s from Digi-Key and played with one driving an IRF-740A. I wasn’t too impressed and it appeared to me that the driver i.c. did not meet spec. Hopefully the Maxim parts are better.

The Microchip parts run out of gas quickly arround 4MHz. They have a lot of internal delay and behave very strangely at frequencies above 4MHz. I was attracted to these parts initially because they offer a 4420 in a TO220 package (~10W dissipation). I evaluated it and the DIP8 version with equally dissapointing results. The Maxim parts are much better.

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Postby Tom WA3KLR » Sun Jan 23, 2005 6:00 pm


Thanks for the feedback on the Maxim version of the 4420's. Yes, I wanted to order the TO-220 version at the time, the TC4429CAT, but it wasn't stocked.

So maybe the Maxim parts will make a good low-cost alternative to the DEIC420 for 160 meters. I will plan to use the DEIC420's on 75 and 40 meters.

Later, I may try a 10 meter deck. The DEIC should be good for this too. I expect to require bonifide RF power FET(s) on 10 meters - an IXYS or APT part. But this is way down the project list, after the power supply, 75 meter deck, PW modulator deck, 40 and 160 meter RF decks are in service!
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