EMRFD Message Archive 9198

Message Date From Subject
9198 2013-10-02 10:20:55 prysm678 ad603aq questions
Hi all

I was wondering if anyone has used AD603AQ, before and had an insight of the actual gain measurement.

I am providing it an input of 25Mhz @ -40dBm I am only getting an output of -11dBm when I set the gain to 40dB. shouldn't I be getting 0dBm? I have feedback resistor of 2.15kOhms.

I blindly followed the termination illustrated in w7zoi spectrum analyzer update, except I changed the bandwidth to 30Mhz.

9199 2013-10-02 23:02:05 victorkoren Re: ad603aq questions

It amplifies 40dB voltage gain. The power gain depends

9200 2013-10-02 23:07:53 victorkoren Re: ad603aq questions

Sorry, my mistake.

After reading again the datasheet, the AD603 has a 40 dB gain RANGE. Its maximal gain is only 

+31dB, so your result is much closer to the datasheet number. Anyway can you describe the test circuit?

Victor - 4Z4ME 

9203 2013-10-03 18:31:10 prysm678 Re: ad603aq questions
Victor You are correct I was not terminating the device properly. I had 50ohm signal Gen so I put a 100ohm resistor in parallel with the ad603 input and for the output I was using a 50ohm power meter with 1kohms in series. Basically this is set of questions while I try to refine my build of qst spectrum analyzer. Do you have a version of w7zoi qst spectrum analyzer? There are a few quirks with my build and wanted to do a comparison.