IC capable of driving 30MHz 10 Vp sin into 300pF

Sounds challenging. I used to love that kind of work. A decade of nothing but very mundane work ruined me.

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JosephKK

I had been thinking along the lines of the old Teledyne Philbrick 1443 ultrafast buffer; it would do at least 100 MHz drive over 2A and would slew about 2500 V/us. The stuff Apex is putting out now make it look like junk.

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JosephKK

The 1443 datasheet features a page of Hi-Frequency Troubleshooting Techniques, well worth a re-read. I enjoyed this paragraph on page 6, under, The finger as an Analog Development Tool.

"In 15V systems, the finger can be a useful investigative tool, if thoughtfully applied. It can couple signals in and out and can also be used as a load. A well-laid-out RF opamp circuit will be only slightly affected by a light touch. Dramatic changes reveal a sensitive point! Check a circuit by touching the amplifier case, the supply rails (carefully), ground, control knobs, chassis parts, etc. If things change markedly when you touch these areas, parasitics may be the problem."

I dunno, they go to higher voltages, but none of them slew as fast as the 1443, for example. Sadly, this limits the value of their higher-voltage capability to below say 5 to 10MHz. For example, their PA19 only slews to 1000 V/us, which means its 60Vpp 2A capability is limited to below 4MHz. Sorry!

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 Thanks,
    - Win

....and anybody's toolbox that doesn't consist of a toothpick with a ferrite slug glued to one end and a brass slug glued to the other end hasn't ever needed to fine-tune an RF circuit.

{;-)

Jim

*Contain*, that I believe. "Consist" is too hard-core for me. I want comfort features like a soldering iron and some diagonal cutters.

You can also tune fixed-value ferrite inductors using a rare earth magnet, at least if you don't have saturation worries. Some stay tuned, and others don't, but you can at least figure out which way it should go.

Cheers,

Phil Hobbs

Don't forget the glue gun.

John

A wooden-cased pencil makes for a more easily tuned tool. Depending on how you grasp it (s/lightly held, or grasped along as much of the length as possible), you can tune the capacitance fairly well. It has the significant safety advantage of some voltage isolation, too. The series resistance is significant; that can be good or bad, depending...

The same kind of ideas as far as its use as an investigative tool apply.

-frank

I could not find spec sheets for the 1443, did you? The summary specs i found on their web site showed stuff that slewed at over up to 1000v/us.

try:

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JosephKK

OOPS. Last time i was at the site i thought i saw stuff at 4000V/us and better. this is supposed to be after my post of their web site.

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JosephKK

Not too sure, but when i was troubleshooting weird problems i had several toothpicks with one or the other on the end. it was often combinations that helped me isolate the problem(s). 2 or 3 times out of hundreds. use of multiple fingers to induce maximum unintended behavior set me on this path.

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JosephKK

I like that part, with its built-in tripler to make the MOSFET gate driver's voltage. But didn't Frank Mikkelsen asked for a sine-wave drive?

BTW, I have the Teledyne Philbrick 1443 datasheets.

--
 Thanks,
    - Win

Is this an invitation for us to ask you to post it on abse? I couldn't find it and your comments on it rose my interest.

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Thanks,
Fred.

Go and get it...

--
 Thanks,
    - Win