#1863

Episode 1963 chip of the day
Gallium Arsenide Transistor zoom zoom
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[@jeffreypomeroy6173]

MESFETs are basically JFETs with a schottky junction instead of the pn/np junction at the gate.

[@Peter-W1]

I called P1dB 1 dB compression point back in the days i measured small amlifiers, and YES "chip of the day" is a favorite 👍

[@deanbell5164]

I like the term 'happy place' for the bias :)

[@hobbified]

PAE is just efficiency with the RF input (drive power) considered as a source of input power. Because with 10dB gain, Pin is equal to 10% of Pout, so just considering Pout / DCin would be ignoring a noticeable chunk of the power entering the amplifier.

[@jsdutky]

Aww. I was hoping for some time on the curve tracer.

[@uploadJ]

For an RF device? As an end user of those devices we have never used a curve trace to look at an RF device, what we have used is manufacturer's 'test circuit' whose diagram and parts list (for impedance matching) is usually shown in the data sheet. Now, as a 'semiconductor fab' (manufacturer) of those devices, **we did** on-wafer testing doing pinch off (Vp), IDSS (zero V on gate and measure source to drain current), and gm (transconductance or DC gain) as these parameters indicate to the product engineers that the various fab steps **did** result in functional 'structures' comprising the device. On wafer DC tests also show which devices are candidates for subsequent mounting in a 'housing' for RF tests.

[@AnalogDude_]

HFA3046, HFA3096, HFA3127, HFA3128 from Renesas is the replacement for the well known CA3046, etc. capable of 8 gHz, not cheap either.

[@BalticLab]

Great video!

[@wa4aos]

metal-semiconductor field-effect transistors (MESFETs)

[@christopherleubner6633]

Ive seen some of these in cellular base stations, usually built into the antenna module block.

[@KeritechElectronics]

HF power transistors are definitely interesting!

[@byronwatkins2565]

Metal (ME) Semiconductor (S) FET. The metal-semiconductor junction forms a Schottky diode rather like the pn junction of JFETs.

[@winstonsmith478]

Using Octapart, Aztech (Italy) has 2,774 FLL120MKs in stock at $1.12 each at any quantity. Partstack confirms that with other high quantities in stock and cheap from other suppliers. If sold for the MUCH higher prices on that auction site, you could make a killing IF there was a significant demand which I seriously doubt seeing that there is only one FFL120 sale shown in a search for completed listings despite the large number of listings for that transistor.

[@joseppuig925]

You can't trust the brokers, they may have fakes in their stock. They have a tendency to state that they have lots of units of the part you are searching for. I think they use a kind of automated script to report back the search query with some random number to octopart, and when you buy it, they "prepare" the ICs for you.

[@TranscendentBen]

4:27 Yeah, that looks a LOT like vacuum tube characteristic curves with negative grid bias! The voltage and current scales do look a little off, though.

[@sundog486]

Yes. I explain vacuum tubes to young whippersnappers by saying they behaved like depletion mode FETs. Then they ask what is depletion mode?

[@Dr_Mario2007]

Kinda funny that it wouldn't be long before computer chips use basically the same stuff as RF transistors (for good reasons as they tend to grip on electrons better than Silicon counterpart especially when transistors get much smaller). Still, HEMTs (high electron motility transistors) are an interesting technology as whole.

[@SimEon-jt3sr]

Why tho can't they just somehow analog and just have crazy gigahertz radio type stuff. Idk how it works. But that's probably the future right? Kind of a blend. Of everything

[@robinbrowne5419]

I wonder if you could remove the lid from one of the FETs and show us what is inside.

[@DiaconescuAlexandru2024]

And I thought buying IRF510's for my DIY RF amp was getting expensive!

[@richysradioroom]

$1.50?? LOL

[@BeesKneesBenjamin]

IRF510 for an RF amplifier?? Are you building an end stage for an LW radio transmitter? I've used them for designing switching powersupplies! :-)

[@uploadJ]

@@BeesKneesBenjamin Believe it or not, the IRF510 can be coerced into operation up to 30 MHz, Now, is it ideal - well, it is cheap so it has that going for it. Do a little searching, there are even vids on the design of HF amps using that device.

[@DiaconescuAlexandru2024]

@@richysradioroom Average salary here in Romania is $400, just the IRF510's were $5 but I also have to buy the other components :)

[@DiaconescuAlexandru2024]

@@BeesKneesBenjamin 50W amp for the 10 meter band, for SMPS's I have MJE13005's and DK112's

[@TheRcEngineer]

This might make a good qo100 amp 2.4 Ghz is out of L Band but the datasheet specs at 2.3 Ghz

[@Clancydaenlightened]

Use it to make a 1 or 2 ghz drsstc But the secondary would have to resonate at a harmonic several wavelengths longer Unless you want 2 or 3 inch secondary

[@Clancydaenlightened]

I don't think that's class E anymore

[@Clancydaenlightened]

Damn now running a Tesla coil will knock out wifi and phone service within a few miles At that resonant frequency

[@richysradioroom]

nice

[@geirha75]

40% efficient? So like 60% of the input power is dissipated as heat?

[@davidsmith9063]

You are SO SO So VERY lucky to have gotten that amp for that price, destroyed or not! That's the kind of thing i can never find for that $$$. Enjoy all of those devices!! I'm absolutely GREEN! 🤓 Thank you for another useful video. have fun with those!!!! - KE5DEV

[@alistairmackintosh9412]

No frequency response curve?

[@ChrisJackson-js8rd]

would that serial number be from the manufacturer or from the seller?

[@JesusSG99]

i want to see your face , you look cute