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MW7IC2425N

Question asked by Vasco Tesi on Sep 30, 2014

We built an RF power generator by taking your test fixture (MW7IC2425N PCB and relevant BOM) exactly "as is" without any modification,  and adding a signal source.with adequate power ( 15 to 20 dBm).

The generator works correctly but with fairly suboptimal performances.

The polarization of first and second stage was set as per datasheet typical values ( no adjusting, but it is possibile to adjust through a DAC).

The pallet under the RF circuit has a good planarity ; the bottom (ground) layer of RF circuit is not soldered to the pallet but is in contact to it due to the screws (each hole in your text fixture is provided with an M3 screw).

The MW7IC2425N ground pad  is tighten to the metal by using bolt down technique and interposing a very thin layer of  5 mil TGON graphite (Laird TGON 805).

 

We realized two generator samples; both have an RF power output less than expected, 22 to 24 Watt while in the datasheet it is reported an output power well above 25 Watt if driven with power between 17 and 20 dBm.  Also the efficiency is less than expected. Both were programmed at 2450 MHz output. 

 

So, in view or building an engineered product we have some questions:

- How did you build your text fixture? It was soldered to underlying metal? MW7IC2525N was bonded to ground through soldering or bolting? What can we do to get better performances / repeatability of performances, is it useful to act on polarization, on MW7IC2425N grounding or grounding of the PCB ? Can you give us some suggestion about the optimal input RF power to achieve maximum efficiency ?

Thanks

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