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I'm working on a test fixture for which I need to generate a 10Vpp square wave, at 13.56MHz, capable of driving 250mA. My first attempt was a using opamps, but very quickly realized I can't drive 250mA, and line drivers that came close can't support the high slew rate input from the squarewave. Then, I thought I could use gate driver ICs, to drive a half bridge which would ensure I deliver the full required power to the load. However, driver ICs don't work at 13.56Mhz. I also ran into trouble finding FETs that can switch at that speed, but found a few from Onsemi that may work. Finally, the most promising solution so far (although I don't have it quite working yet) is to use two opamps to drive a FET-based push-pull output stage. However, I'm running into issues with the op-amps driving the FETs fully on, capable of handling the high sink/source gate currents needed for switching these at high speeds.

I also thought of using an NFC reader IC, since they readily generate a carrier wave driving a >250mA load ( I think) --but these chips do much more than I need and I'm not ready to be that wasteful (yet).

I'm currently experimenting with these potential solutions with LTSPICE- everything has only been simulated, not built.

Here are some sketches of my initial concepts:

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I'm looking for some suggestions. Is there a better way to do what I'm trying to do?

Thank you.

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    \$\begingroup\$ Some hams get a few watts from a single MOSfet running class-E. The gate drive might be as simple as 5V HCMOS logic gates. \$\endgroup\$ Commented Dec 1, 2020 at 16:00
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    \$\begingroup\$ Why? An insanely powerful, harmonic-rich square wave with a 9th harmonic in the aviation band should prompt caution. \$\endgroup\$ Commented Dec 1, 2020 at 16:09
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    \$\begingroup\$ ... and then you filter it to make a sinewave? Doesn't make sense. \$\endgroup\$ Commented Dec 1, 2020 at 16:11
  • \$\begingroup\$ If you really insist on doing it this way: there are driver ICs that will work at high frequencies (not sure about their maximum frequencies, though), like the LMG1210 and the PE29100, and some GaN FETs that would work can also be had. But why? \$\endgroup\$ Commented Dec 1, 2020 at 16:20
  • \$\begingroup\$ What do you intend on being the first, 13MHz source? It might make sense to revisit that rather than take it, heavily clip and distort it and then filter it again. \$\endgroup\$ Commented Dec 1, 2020 at 16:52

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