HW fixes

A project log for Microwave Transmitter

30 - 6000 MHz synthesizer with power amplifier

PeroPero 06/09/2017 at 08:252 Comments

After my honeymoon trip and triathlon race, I finally found the time to fix those bugs. Broken LDO was replaced by some similar 3V3 LDO in SOT 32-5 package from an older project. It did the job well, and 3V3 as well as other voltage, were present at their places.

RF detector on the other hand was a bit more difficult thing to find. Log detector LMH2110 that I lost was available only from Digikey, that would charge me additional $20 for shipping on $1 of chips. The retailer that has lower shipping costs in my country, RS components, only offers another chip in the same package with the same pinout: LMH2120. Thing is, this is a linear detector. But, since it was cheaper solution, I decided to give it a try. I'll worry about log/lin issues later.

It was the same pain soldering it as before. However, I didn't use hot plate, although I planned to do so. I've put a bit of solder on those tiny BGA pads and covered them with flux. Then, I placed the chips, carefully under the microscope. And finally, I soldered them using the hot air gun, high temperature but very low air speed. I usually don't use microscope when working with SMT, but for chips this size, it was detremental. In any case, chips got soldered, though I'm not 100% sure if they're placed in the right way.


Tegwyn☠Twmffat wrote 06/10/2017 at 08:08 point

Nice work! I'm testing the Analog devices AD8318 at the moment for RF detector / RSSI. You can buy it from Mouser, who pay the customs fee so no $20 additional shipping:

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Pero wrote 06/11/2017 at 21:34 point

looks like a nice chip! If I had thought it well through I would probably choose better than 6-ball BGA component...

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