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problem in testing the MMIC2 evaluation board

Question asked by hwangyt on Oct 12, 2017

We have recently purchased an EVAL-RADAR-MMIC2 evaluation board and encountered some difficulties in testing it. We basically follow the evaluation and test procedures outlined in the user guide (UG-866) to test the board. The evaluation software was set up to control the IC settings in the evaluation board through SDP board.

  1. The first problem we encountered is the correct setting of ADF 5901, 5904 and 4159. The user guide does not disclose any specific settings and we are not sure if the default settings work or not. However, we did manage to set the VCO frequency of 5901 to 24025MHz and tried different frequency ramp up setting
  2. The first test we conducted is the transmitter output. The TX_OUT2 of the evaluation board is connected to a spectrum analyzer to see if the RF signal frequency is indeed 24025MHz. A 5V power supply is connected to the board. Surprisingly, the voltage drops gradually to about 3.2V according the reading shown in the panel of the power supply and the current drawn by the board varies from 0.08 to 0.12Amp. Although we suspected if any abnormality or short circuit of board causing the voltage drop, no unusual heat dissipations were observed on these chips. From the spectrum analyzer, we did see a signal peak shown in the screen. The frequency of the peak, however, is around 23.5GHz rather than 24.025GHz. This frequency also varies within a vicinity of about 300~400MHz. We are not sure if this is due to the frequency ramp up of the generated FMCW. It is supposed to be 200MHz at most according to the data book. Trying different ramp up options does not yield significant difference in the observed spectrum. We also tried the one sweep only option and expected a constant frequency output after the sweep, but the peak in the spectrum remains hopping back and forth all the time.
  3. We also connected the TX output to one of the four RX input, connected the evaluation board to D2S, and then used the spectrum analyzer to observe the received signal. This time, nothing was spotted.

That’s what we have tried so far. We would appreciate greatly if you can

  1. Point out possible mistakes or missing points in our test trials
  2. Provide us with a detailed setting example
  3. Figure why the power supply voltage drop after powering up the evaluation board

 

Attached please find the configuration file we used in testing the borad

There is also a video clip showing how we did the test. At the beginning of the video, the reading of the power supply shows that the setting is 5V. However, after we power on the board, the voltage drops to 3.1V. The video next shows what we got from the spectrum analyzer. A single ramp burst mode was used and the frequency is set to 24.025GHz.

The peak of the spectrum, however, is centered at 23.23GHz and moves back and forth.

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