Re: MMIC question


Mike Willis
 

Hi Richard

Assuming via a RF choke. There is no problem until something goes wrong. A resistor will limit the maximum current. If you have say 30mA and a 12V supply you need to drop 7V so probably a 220 ohm resistor. If the device goes short circuit you would only take 55mA or so from the supply.  Without a series resistor there is no limit, so if the device goes pop, so potentially does the USB port. Most MMICs will run of a bit less than 5V, might be worth dropping a volt or two. Also include a polyfuse.

Finally, if you want to generate RF noise, running directly of a USB supply is a good way to achieve it.

Mike

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