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Re: Chinese 15W Amp
Posted: Mon Dec 06, 2021 5:15 pm
by yellowbeard
One of us needs to pull out the tree fiddy and get one of these:
https://www.hf-electronics.nl/Uni-Eindt ... 5-MRF101AN
Re: Chinese 15W Amp
Posted: Tue Dec 07, 2021 12:36 am
by Bton-FM
Perhaps you could just copy it from the picture. The circuit isn't that complicated: It's just a bias circuit and impedance matching.
The matching for the MRF101 is taken from the circuit in the datasheet.
Re: Chinese 15W Amp
Posted: Mon Dec 13, 2021 10:01 am
by reverend
That's OK but it needs component values calculating depending on the use. You could make something similar with squares of PCB cut out and stuck onto a single-sided copper clad PCB (which is exactly what I used to do in the old days). It would be good to have some of the input component matching etched onto the board, but this might not be difficult with too wide a range of transistors due to the different input impedances (it might just be possible to use additional padding capacitors/resistors on the input of the transistor to make them all the same). The output match is going to change massively with supply voltage / output power so these would have to be calculated seperately for each device.
Lots to think about!
Re: Chinese 15W Amp
Posted: Mon Dec 13, 2021 1:57 pm
by jvok
Looks like that hf-electronics.nl link is only for a blank PCB so you'd probably have to design your own matching circuit anyway. They say they have a schematic for the MRF101 but as Bton said that's probably just the one off the datasheet. And for the RD06 and RD15 you're on your own.
NXP have a complete reference design for the MRF101 for FM band (and other frequencies too). Look under Design Resources at the bottom of the page:
https://www.nxp.com/products/radio-freq ... AN-REFCirc Annoyingly you have to sign up before they let you download the zip file but it does have the full layout and BoM. No schematic for some reason but the boards simple enough you can trace it out pretty easily.