Modern transistors for HF/VHF Class-E, 10W, 100W ? - Page 1
Forum section: electronics / rf-microwave

author: fourfathom
author_rank: Super Contributor
timestamp: June 22, 2025, 05:03:39 am
content: I'm contemplating the design of Class-E (or class D) power amplifiers for the 1-60 MHz range. I need 10 Watts output (and possibly 100W later in a different design). Can anyone recommend some transistors I should look at? Obviously these are not linear amps -- these will be constant-amplitude, long-duration duty-cycle, running FSK or PSK modulation.There are lots of new MOSFET families and I haven't been keeping up...Thanks!-Paul / wb6cxc

author: RFDx
author_rank: Regular Contributor
timestamp: June 22, 2025, 06:36:03 pm
content: Compared to class-E, voltage mode class-D (VMCD) is more suited for broadband operation but needs two MOSFETs (push pull) and output filtering that terminates harmonic frequencies into a high impedance. An advantage is that the VMCD amplifier can be driven by a squarewaveorsinewave. The bandwidth of the output balun is a challenge as it has to cover both the the fundamental and (at least a few) harmonic frequencies.RF LDMOS transistors can be used, something like the RD16HHF1 and MRF101A(B), both in TO-220 case, for the 10W respectively the 100W variant.

author: stretchyman
author_rank: Regular Contributor
timestamp: June 22, 2025, 07:33:26 pm
content: Nexperia GaN HeMT.1.2nC Qg so easy to drive. Cant remember the model.Choice of driver is an interesting one.Fine upto 15MHz, forget above 30MHz.Ive no need to go any higher so no idea how youd get to 60MHz with class E/D.I dont think the previous reply understands your requirements. LDmos are low voltage and of no use. Infact most RF devices are useless and stupidly expensive in this application. Youll be using the latest power devices. Modern and cheap but only good to 20? MHz.I've been building 10W, 50W and 100W carrier class E a.m. transmitters for the last 12 years.Ive done a fair few experiments so can give you some advice.100V devices for 10W and 600V devices for 100W +IRF520 is fine for 15W sub 10MHz, GaN for anything higher (Transphorm). Higher frequencies require smt FETs and very fast drivers.

author: fourfathom
author_rank: Super Contributor
timestamp: June 22, 2025, 10:55:18 pm
content: Thanks to both of you!I'm looking at Class-E because it's a simpler design, but I am familiar with Class-D and similar designs. I currently have a design that has eight 1W output ports, each using four 74ACT244 bus drivers, in an H-bridge configuration (lots of paralleled outputs) capacitively connected to a wideband 1:2 transformer. These ports can deliver a +1W square wave from 1 to 50 MHz (the efficiency is down at 50 MHz but is still useable). The ports are connected to a multistage series L/C filter network, which provides a high impedance load for the harmonics (and filters the harmonics to meet FCC spec). The filters also go high-Z above and below the design frequency, allowing me to combine multiple 1W outputs together to drive a multiband antenna. This is used in radio propagation and ionospheric research -- if you're curious here's a link:https://turnislandsystems.com/product/wsprsonde/. We have these running in Antarctica, at practically the North Pole, and many places in between.So now I've been asked to provide 10W or more per channel. I hope to use the existing unit to provide the drive for some external 10W amplifiers. It would be nice to have the amplifiers be broadband 1-60 MHz with center-tapped push-pull outputs (unless I can find a PMOS complement!), with external filtering as I am doing now with the 1W design, but if not I would use specific-frequency Class E and design the output matching / filter network to allow for combining multiple bands.1W of drive seems like a lot for a 10W amplifier, but I can (under software control) reduce the power output to 250mW.So I've been looking at MOSFETs that seem to be targeting high-speed switching regulators. There are also lots of expensive high-power MOS parts that work well into to the GHz zone, but I suspect I don't need that performance.BTW, I'm a retired engineer, this stuff is now my hobby.

author: rf-fil
author_rank: Regular Contributor
timestamp: June 23, 2025, 12:28:29 am
content: A little nitpick.. PSK is rarely used in its raw unfiltered form. The instant phase changes would make the signal very broadband (and cause splatter all over the bands for HF ham use case). In practice, PSK style signals are processed through some form of pulse shaping, like Root Raised Cosine for example. This filtering reduces the signal bandwidth, improves SNR at receiver, and also adds a significant component of AM to the signal.

author: rf-fil
author_rank: Regular Contributor
timestamp: June 23, 2025, 12:30:13 am
content: Btw, I think you'll have the easiest job by just using Mitsubishi RF LDMOS devices. They are designed for this, and not that expensive. Trying to use switch mode MOSFETs just makes it harder.

author: fourfathom
author_rank: Super Contributor
timestamp: June 23, 2025, 12:49:12 am
content: Quote from: rf-fil on June 23, 2025, 12:28:29 amExcellent point, but trust me, I know about PSK, baseband filtering, and modulation spectrum. And how a basic constant-amplitude Class-D (or other) amplifier behaves.

author: stretchyman
author_rank: Regular Contributor
timestamp: June 23, 2025, 07:27:56 am
content: LDMOS won't be of any use and using switching mosfets is simple.Please no more LDMOS, fine in a linear, not so for a switching generator.Class E will give X 3.5 V supply on the drain so you're not going to get far with a 50V device.Personally I wouldn't use >6V on the drain of a 50V device in class E.Look, I've built hundreds of these things and gone thru' all the designs I could find with plenty of accidents so I speak from experience what will work and what will not.Upto 10MHz any half decent power fet will work as long as the Qg <10nC and your using a decent driver (I used to use NCP81074 but there are better now but fine to sub 10MHz).Above 20MHz you're going to struggle and certainly wont be using any cheap power devices.I've no idea what RF devices are available, they wont be LDMOS that's for sure and GaN HeMT with a low Qg (<2nC) and 600V is the current trend.Anything 'RF' attracts a stupidly expensive price whilst the latest GaN power devices are $2-3.If you can find a devices that gets the gate charge even lower then the driver is the next 'problem'.I get efficiencies in the high 80%'s, occasionally 91% with CMCD with frequencies upto 15MHz.Have a look thru' this lot. Infineon bought GaN Systems a while ago;https://www.infineon.com/cms/en/product/power/gallium-nitride/gallium-nitride-transistor/https://www.infineon.com/dgdl/Infineon-IGLR70R270D2S-DataSheet-v01_00-EN.pdf?fileId=8ac78c8c93dda25b01951e5e2a6a0cc7Looks promising..

author: fourfathom
author_rank: Super Contributor
timestamp: June 23, 2025, 07:08:54 pm
content: Quote from: stretchyman on June 23, 2025, 07:27:56 amThat last one does look quite promising! If necessary I can limit my frequency range to 1-30 MHz. 60 MHz would be nice, but not necessary just yet. I've got a mind to put two of these on a board to drive a center-tapped transformer (using the configuration with a choke feeding DC to the center tap), and see how far I can push it for frequency and power in the class-D mode. I've got plenty of drive power available.

author: rf-fil
author_rank: Regular Contributor
timestamp: June 24, 2025, 03:43:12 am
content: LDMOS used to be the "low capacitance tech".. Looks like I am behind the times, and need to checkout some of these "non-RF" GaN devices. Their voltage rating & capacitance look amazing.

author: Weston
author_rank: Regular Contributor
timestamp: June 24, 2025, 04:28:12 am
content: Class E is tuned, so what frequency are you operating at? And any external Drain - Source capacitance requires a low inductance, so you can't easily implement it as a switched filter bank like is used for band-switched filters. Or are you talking about multiple designs that you want to use a common transistor for?GaN devices look really nifty, but I would avoid them for this. They are very fragile. Small die size so its easy to overheat if you loose zero voltage switching, they cant avalanche, so mistuning can kill them with over-voltage, and the gate has a limited operating voltage, so you can't use resonant gate drive and require a very low inductance gate drive and a robust gate driver. On top of that, the output capacitance is lossy, so you don't get the efficiency you expect.You might be able to find some MOSFET designed for SMPS that works to some 10's of MHz but it can be a gamble, not all of the properties that are important are captured in the datasheet.I would recommend LDMOS parts. The MRF101 is a decent part but a bit overpriced. I built this a while ago which is pretty close to what you want. 40W at 40.68MHz, 91% efficient . report PDF is in the repohttps://github.com/westonb/Plasma-DriverAlso consider push pull class E, its an easy way to get more power.NXP has a 40V line of LDMOS parts that might be more cost effective and would run at a ~10V supply.AFT05MP075NR1 push pull device, best bang for the buck for any RF device in any class up to 500MHz. I built a nice linear wideband amp with it

author: fourfathom
author_rank: Super Contributor
timestamp: June 24, 2025, 05:06:03 am
content: Quote from: Weston on June 24, 2025, 04:28:12 amIf I can come up with a broadband (squarewave) design that would be great, and I would use external filters. But if it's going to be a Class E then perhaps the same transistor/layout with a fixed-tuned L/C matching network -- different assemblies for different frequencies.QuoteI've got a lot to learn and digest. And there are definitely some strong opinions here! I've designed and built some low-power (1 W +/-) Class C and E amplifiers in the HF range, but this is new territory for me. I keep thinking that a 10 Watt output shouldn't be that hard, but I'm definitely in the "analysis paralysis" stage at the moment.

author: stretchyman
author_rank: Regular Contributor
timestamp: June 24, 2025, 05:24:31 am
content: Oh no another LDMOSer, please no more.10W just use and IRF520 upto 10MHz and something GaN like after that.Low Qg and high Vds is all you care about!Yes class E is a narrow (single) band design

author: rf-fil
author_rank: Regular Contributor
timestamp: June 24, 2025, 06:06:07 am
content: Isn't class E quite sensitive to its load impedance? So it would get de-tuned and loses efficiency quite easily, compared to a class C. Not a big issue with a fixed pre-tuned HF antenna, though.

author: stretchyman
author_rank: Regular Contributor
timestamp: June 24, 2025, 06:32:03 am
content: Yes it's narrow band, so a single band (100KHz@7MHz) one of the reasons why it's so efficient!Look (again) I've built 100's of these things from 10-200W (40-800W) pep and have spent the last 10+ years doing nothing but that!I'm no 'Expert' but do have a lot of experience.So why recommend a 40V part when the Peak voltage will reach 42?The LDMOS parts I've seen are all low voltage and all the GaNs are 600V-750V, so no concerns about over voltage.Thinking.....There are some 100V GaN sytems (now Nexperia) parts that I've use in my modulators and (may) be fine for 12V use, never tried them tho'.Just to add... There's a world of difference between merely 'looking' at designs and actually building them and making them work well.

author: stretchyman
author_rank: Regular Contributor
timestamp: June 24, 2025, 06:40:59 am
content: CMCDMy first try at CMCD, a tad cramped but works fine.3 GaNs per side with a single driver 60W@36V, 89% eff @ 12MHz.Balun is 1:1 coaxial and you feed each side with a choke with tuned circuit between.However for your application and upto 10MHz you may as well just use an IRF520 as 10W+ is easily achieved @ 12V using single ended aka LULU.Transphorm (now Renesas);https://www.renesas.com/en/document/dst/tp65h150g4ps-datasheetfor f>10MHz.Driver;https://www.ti.com/product/UCC27614

author: mtwieg
author_rank: Frequent Contributor
timestamp: June 24, 2025, 01:21:25 pm
content: LDMOS is still feasible at these frequencies, but the only advantage they actually have now over GaN power transistors is perhaps better thermal management. If that's not an issue (probably not if you only need 10W of output), just use GaN devices.As for operating across 1-60MHz bandwidth, I'm assuming that's not actual modulation bandwidth, just a range for the carrier frequency. Even so I'm that seems infeasible. You could probably make the gate drivers and FET(s) operate over such a wide range, but all the LC components on the drain side would have to change, by a great deal. You'd either need a ton of relays to switch in different LC networks, or just split the bandwidth into many bands and build completely separate amps for each.As for modulation, FSK probably isn't an issue so long as the bandwidth is reasonable. PSK I'm not so sure about. Instantaneous phase changes violate the fundamental operating principles that these amplifiers are based on...

author: stretchyman
author_rank: Regular Contributor
timestamp: June 24, 2025, 02:27:46 pm
content: Def not trying to cover a 60MHz B/W as that would be very silly.Class E generates very little heat, 4 x TO-220 devices pushing 400W+, not a problem and barely gets above room temp, infact with improved cooling and higher voltages and less current running a higher Z then 800W from the same devices isn't much of an issue.The only heat generated is the power loss across the device when it's on so I2R. 2A thru' a 100mR device is <2W for all 4 devices. 100 or so volts and there's your 800W.If you change the frequency of a class E transmitter as long as it's less than +/- 1% it wont mind neither will changing the amplitude from 0-200% as you would with A.M.I've never tried FSK or PSK only A.M. but I'm interested to see the experiments!Please keep us informed..

author: fourfathom
author_rank: Super Contributor
timestamp: June 24, 2025, 02:39:13 pm
content: Quote from: mtwieg on June 24, 2025, 01:21:25 pmYes, my 1-60 MHz goal is the carrier frequency. The modulation is extremely narrow / slow 4-FSK (symbol rate is sub-2Hz). Experimentally we may add BPSK to this (for timestamping in time-of-flight/arrival studies). The BPSK rate will only be a 100 Hz or less, to keep the raw infiltered BPSK occupied bandwidth within the ham radio specs of 2.4 KHz. BPSK isn't a requirement yet, but class E can certainly handle regular PSK.Yes, Class-E is fairly narrowband (about 10% of carrier freq, depending on the matching network design).As for a single amplifier covering the 1-60 MHz range without LC network changes, I'm already doing that at the 1W level. This is an H-bridge design using 74ACT244 bus drivers feeding a wideband ferrite transformer, providing a 1W square(ish)-wave output into a 50 Ohm load. All filtering is done externally and these are indeed fixed-frequency filters. The efficiency isn't much better than 50%, but it suits the purpose very well. This is all constant-amplitude stuff -- I don't need or want linearity.Of course this is easy at the 1W level, but at 100W, or even 10W, then efficiency becomes critical, and the solution isn't so obvious. That's why I'm looking for advice and ideas. I appear to be heading towards a per-band Class-E design.

author: stretchyman
author_rank: Regular Contributor
timestamp: June 24, 2025, 02:59:18 pm
content: Oh, you are trying to cover 1-60MHz with a single amp!Well you wont be using any class E design then but you will be able to use one of those horrible LDMOS linear things!Seriously tho' its obliviously depend on so many factors and any 'Broadband' design is going to be class A/B linear with it's inherent poor efficiency etc. Loads of designs around for those and again IFR devices will be fine along with the LDMOS's.I don't think class E is anywhere near what you want as you will need single band designs for each frequency (band), which whilst being efficient your are going to need quite a few!

author: fourfathom
author_rank: Super Contributor
timestamp: June 24, 2025, 03:18:02 pm
content: Quote from: Weston on June 24, 2025, 04:28:12 amWeston, looking at that schematic I see the "LMG1020 5-V, 7-A, 5-A Low-Side GaN and MOSFET Driver", with 5V, 5A drive capability (https://www.ti.com/lit/ds/symlink/lmg1020.pdf). I wonder how much power I could actually coax from that in a single-ended or bridge configuration (using just that driver by itself, similar to what I'm currently doing for the 1W output)? The BGA thermal specs look to be nor impossible(?)Otherwise, that's a nice part, and makes the Class-E/D design a bit easier!

author: mtwieg
author_rank: Frequent Contributor
timestamp: June 24, 2025, 03:23:41 pm
content: I don't believe there's any way for a switchmode PA to operate over such a wide frequency range without switched L/C components. And by "operate" I mean operate as intended for its topology. Sure you can drive a class E/D PA at five times its intended frequency, but it's no longer going to operate with the ZCS/ZVS conditions it was intended to achieve. It effectively won't be operating as class E/D anymore.Is the load/antenna broadband across that frequency range? If not then even with a linear PA you would need some sort of adjustable tune/match network. Or would you be swapping the antenna manually depending on the carrier frequency?

author: fourfathom
author_rank: Super Contributor
timestamp: June 24, 2025, 04:32:40 pm
content: Quote from: mtwieg on June 24, 2025, 03:23:41 pmDefinitely not class E -- that requires tuned circuits to achieve ZCS/ZVS. My 1W bridge design does not do either ZCS or ZVS, and I was hoping to find a switching circuit that was fast enough at the 10W power level to not need ZCS (and keep the efficiency tolerable). Perhaps this is not practical, and that's why I am trending towards fixed-frequency Class-E.QuoteThe antennas used in my systems are multiband, with a decent match at the design frequencies, and my 9-channel filter-combiner network (essentially a 9-plexer) provides a matched connection to each amplifier output. This would work with individual tuned Class-E amplifiers, but at the 10W level I will have to upgrade my filter-combiner.This all goes into a multiband, simultaneous output transmitter used in ionospheric propagation research, with eight 1W outputs that are combined into one port that feeds a multiband antenna. Alternately, multiple antennas can be used, with individual filters at the amplifier outputs. If you're curious here's a video of a presentation I made at the 2025 Dayton Hamvention, where, among other things, I describe the system, 1W amplifier stages, and the filter-combiner:https://youtu.be/S9-LE3al2G4?t=1659

author: mtwieg
author_rank: Frequent Contributor
timestamp: June 24, 2025, 04:50:50 pm
content: Quote from: fourfathom on June 24, 2025, 04:32:40 pmAll of these topologies are, by definition, based on either ZCS or ZVS.QuoteOk so you're not fixating on optimal efficiency, but the 10W across a wide frequency range is the real goal.But if 50% power efficiency is already acceptable, then why attempt to use switchmode PAs at all? Doesn't a class AB PA suit your needs much better?QuoteKeep in mind that the operation of switchmode amplifiers depends not only on the load impedance at the carrier frequency, but also at odd (and also even for class E) harmonics as well. This is another reason why making switchmode PAs flexible is a problem.QuoteInteresting, I'll have to sit down and watch this when I get the chance.

author: stretchyman
author_rank: Regular Contributor
timestamp: June 24, 2025, 05:04:24 pm
content: So its simple then!Either 9 class E or 1 LDMOS linear.Ivs seen RF GaN designs for 100W and they covered 20MHz-6GHz and they were no tune!How about that!.C'mon you've already built a 1W design so why re invent the wheel, just scale it up.

author: fourfathom
author_rank: Super Contributor
timestamp: June 24, 2025, 05:53:48 pm
content: Quote from: stretchyman on June 24, 2025, 05:04:24 pmYes, linear was actually my first thought. But how much IMD will there be in an amplifier with eight simultaneous 10W (output) signals spanning 1-60 MHz? The linear amps I've seen still have switchable harmonic filters, and I need true broadband coverage. But a single 100W amp for eight 10W carriers sounds pretty good, if this is practical.Yes, X/Y problem, I guess! But regardless, I still want to know how to do the per-channel design.

author: Perrold
author_rank: Contributor
timestamp: June 24, 2025, 11:08:38 pm
content: Another vote for LDMOS. The MRF101 is a good entry level starting point. Had a few prototype circuits I wanted to try out and I bought several expecting to blow a few which has been the case with every other solid state amplifier project that was not fully thought out from the starting point. Nope, couldn't kill it. The rest of the devices got taken out of their antistatic bags only for yet different projects. With care I was able to push efficiency to around 94% on 20m with a tuned output circuit and in a broadband design it can output over 50W without anything complaining or being abused. Resonant gate drive is a breeze. Linearity is fair as well if you have an application that requires it. The price tag is steeper than power supply FETs but the ease of use, good performance, robustness, and so forth more than justify it.

author: mtwieg
author_rank: Frequent Contributor
timestamp: June 25, 2025, 12:29:23 pm
content: Quote from: fourfathom on June 24, 2025, 04:32:40 pmOk I watched your video and apparently I still wasn't grasping what your system is doing:1. You have 6/8 PAs of the same design, but each operates only in a very narrowband range.2. All PAs may be transmitting simultaneously. No amplitude modulation (except the option to reduce power by 6dB). I'm guessing all need to be operating CW.3. The PAs are feeding a large combiner (the "9BFC") specifically designed for this setup. Each input port of the 9BFB is narrowband, and each is tuned to a different band.4. The 9BFC feeds a single multiband antenna.Assuming I got that all right, a few comments:1. There's no need for each PA to actually have a wide frequency range. It's just convenient for the sake of "modularity".2. Perhaps a good compromise would be for all the PAs to have a common board layout, but each would be made narrowband to a specific frequency by component selection.3. One of the big unknowns to me is the isolation between ports of the 9BFC. Depending on that, you may want to avoid trying class E or CMCD, as their effective output impedance is actually highly dependent on incident power at their outputs (both phase and magnitude). This could lead to some very strange intermodulation issues.4. In theory the VMCD, on the other hand, can be modeled as a perfect thevanin equivalent source (with near zero output impedance) regardless of incident power, and thus should not suffer from any intermodulation issues. Of course that's just in theory, in reality the switching speed of the driver (rise/fall times of each transistor, plus the dead time between them) will cause some degenerate behavior. But likely still much better than CMCD or class E.5. On the other hand, the power efficiency of VMCD is much worse than CMCD and class E as frequency increases (mainly due to capacitive losses). Using GaN devices extends the useful frequency range of all topologies, but even so getting 10W from a VMCD at above 10MHz may be quite difficult (with available devices, that is).6. You noticed the LMG1020. That is indeed an amazing part, which my lab used as a gate driver in a >120MHz CMCD design. However that was a pulsed application with a very low duty cycle, which is how we got away with such a carrier frequency. But its 60MHz spec might be perfect as your VMCD building block. Yes, it was an absolute b*tch to solder by hand.7. There are other single-chip bridges available that might work. Like the LMG2100R044 from TI, or the EPC2152 from EPC.

author: fourfathom
author_rank: Super Contributor
timestamp: June 25, 2025, 03:26:21 pm
content: Quote from: mtwieg on June 25, 2025, 12:29:23 pmCorrect. To clarify, in most installations the eight channels are configured (via software) to operate in the WSPR regions of the HF ham bands, and the 9BFC is designed for this. But a channel can be set for any frequency between 1 and 60 MHz, and the 1W PA will operate over this range. The modulation can be constant-amplitude FSK, on-off keying, or continuous carrier -- no amplitude modulation or envelope shaping. In some cases the "WSPRSONDE" feeds individual antennas through single-channel filters. This is one reason I am interested in single-channel 10 or 100W amplifiers.QuoteYes. But if I can get or make a truly linear amp that can handle simultaneous signals spread across the 1-60 MHz (or 1-30 MHz) range with acceptable IMD / harmonics then this could simplify my task because I won't need to design a new high-power 9BFC.QuoteThis is indeed a concern. The 9BFC has about 20dB or better adjacent-port isolation, and this might cause IMD problems with a traditional linear amplifier. The VMCD 1W "switching" amplifiers I have now are fairly immune to this. Here's the spectrum at the output of the 9BFC showing very little IMD. Most of the hash is harmonics or clock-synthesizer fractional-divider artifacts, but there is definitely some IMD:QuoteThanks for the feedback and advice! Fortunately this isn't a "do or die" project, just "nice to have", so I have time to get familiar with the issues and methods.

author: RFDx
author_rank: Regular Contributor
timestamp: June 27, 2025, 09:32:13 pm
content: Quote from: fourfathom on June 25, 2025, 03:26:21 pmWith n = 8 tones, each having P = 10 W, you have an average power of n x P = 80W. The problem is that the power amplifier has to be capable of n² x P peak power, that is 640 W PEP. Running the amplifier in class-AB will not be sufficient because of a substantial amount of harmonics (and IMD) which you can't remove with only a single output lowpass filter.

author: fourfathom
author_rank: Super Contributor
timestamp: June 28, 2025, 02:59:22 am
content: Quote from: RFDx on June 27, 2025, 09:32:13 pmYes, you are absolutely right. I hadn't put enough thought into the requirements for a single linear amp. I guess that's why I started to look at individual Class E/D amps -- I'd much rather deal with fat toroids and high-voltage caps in a 10W/channel combiner than a KW amp having an unobtainable IMD requirement.

author: stretchyman
author_rank: Regular Contributor
timestamp: June 30, 2025, 12:50:08 pm
content: If you want the gerbers for programmable 10W pcb just let me know. About the size of an adult thumb. Good to 10MHz bit higher with a GaN.

author: fourfathom
author_rank: Super Contributor
timestamp: June 30, 2025, 04:09:53 pm
content: Quote from: stretchyman on June 30, 2025, 12:50:08 pmI would appreciate that! I'm willing to give up my 60 MHz requirement, but I really want to be able to hit 30 MHz. But even a solid 10 MHz design gives me something to dig into. Here's my email:paul (at) TurnIslandSystems (dot) comPlease send me a link, or the files directly.-Paul

author: JohnG
author_rank: Frequent Contributor
timestamp: July 01, 2025, 04:06:26 pm
content: To see what you can do with low cost GaN, take a look at this:https://epc-co.com/epc/products/evaluation-boards/epc91116While the demo board is expensive, the design info including Gerbers, schematic, and BOM are on the web page for you to use, and the quick start guide shows that you can easily get 100 MHz using a CMOS logic IC as a gate driver. The board is rated to 40V due to bus capacitor ratings, but the FET itself is rated to 80V, and there is an industrial qualified equivalent rated at 100V. The big question would be power dissipation in the GaN FET, but that's a pretty straightforward calculation. You can probably handle a couple amps RMS without too much concern, and that should be enough for 10W easily.John

author: stretchyman
author_rank: Regular Contributor
timestamp: July 07, 2025, 01:42:27 pm
content: Just to prove how simple and efficient a design can be I experimented with some modernish devices back in 2019 and came up with this;https://www.hfunderground.com/board/index.php?topic=55227.0BTW it's just copied from the original patent;https://people.eecs.berkeley.edu/~culler/AIIT/papers/radio/Sokal%20AACD5-poweramps.pdfFor simplicity it's still hard to beat and whilst some folk seem to think class E is is somehow difficult I'd say it's the easiest of classes to build (maybe D is even simpler), doesn't need bias and only 2 components to piddle about with.You can even use an IRF520 here and get 60W peak from a 50p device. BTW an IRF510 wont work as they 're ALL fake!Tune with a 'scope to get the desired waveform.Efficiencies in the high 80's%Marvellous!J.