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How to power the AD5933 evaluation board?

I recently bought  EVAL-AD5933EBZ. 

I have a question to ask before using the device: 

Will, connecting the eval-board to computer PC ,going to power the onboard components like AD5933 , MCU and others ? or I have to design separate power supply.

Please reply

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  • Please refer to your board user guide UG-364. On the first page it says: "The user has the option to power the entire circuitry from the USB port of a computer." Most likely the board has arrived configured to be powered from the USB port. You can double-check by making sure the jumpers on the board are set as described in Table 1. of the guide: LK5 should be in place and LK6 in position A, also refer to Figure 33. Linear Regulator on the EVAL-AD5933EB Evaluation Board.

  • Thanks, 

    Coming to calibration of the evaluation board,

    I don't find any option to adjust the feedback resistor (RFB) in the front panel of the evaluation board software. While reading the user guide UG-364, I found this " note RFB = 200 kΩ. Is it already programmed value. Cant we change this value ? How to change RFB in the evaluation board? Please reply. 

  • Hello!

    Hope everything good from your side.

    I want to clear some doubts related to AD5933 IC w.r.t external clock pin ( pin number - 8 ).

    Actually, I want to do a low-frequency sweep of less than < 5000 Hz. In the eval board datasheet, it is mentioned to reduce the external clock for this. 

    In the UG -364 datasheet, page -20, table-2, Freq's - (4, 2, 1 ) MHz is used for low-frequency sweeps. In the evaluation board, 4 pins SMD external oscillator was used.  

    Question-1:  Can I use a function/waveform generator to drive the pin-8? Is it sinusoidal or square wave? If yes, is the peak-peak voltage = 6.6 V(3.3 V-(-3.3 V) and amplitude =3.3 V setting fine?

    Question 2: Or Do I need to use a 3.3 V crystal oscillator of a specific frequency for this.

    Please help.

    And do you have any idea about the availability of AD5933 IC? For almost a year, it is showing unavailability in stock. I am really worried about it. Do you have any idea about this? Please guide me. It is affecting my work badly. My guide asking me, whether this chip is being manufactured or not? 

  • Question-1

    You most certainly can use the external lab generator to provide variable-frequency MCLK. Per User Guide, Fig. 31. p. 23 you need to remove LK3 while keeping (or putting) LK4 in place and connecting the generator output to connector CLK1. The voltage should be a digital square wave meandering between 0 and 3.3V. Depending on the model, some generators might have such digital output.

    And do you have any idea about the availability of AD5933 IC?

    I am not affiliated with the ADI and cannot comment on the availability. Hopefully somebody from ADI could help you with that.

  • Thank you!

    What connector should I use to connect the external laboratory function generator to the CLK1 of the AD5933 Evaluation board? CLK1 is a SMB socket that I read in UG-364 Datasheet.

  • I found this connector which is SMB to BNC on the Digikey site. Details as below:

    BNC MALE TO SMB FEM, RG174, part no: 24-415-0200-MM500-ND. Can I use this?

  • This should work. A less solid but workable solution would be to get some piece of cable with BNC connector on one end (those tend to float around) and just connect the shield to the Demo Board ground and the signal wire to the exposed part of the LK4. 

  • Hello!

    This is about arduino-AD5933 interfacing!

    I am using arduino-ad5933 code available on , https://github.com/mjmeli/arduino-ad5933.

    I calibrated AD5933 IC , using RFB = 1 K Ω and R_calibration = 10 K Ω. The results of unknown impedance are fine. The problem I am facing are listed below: 

    1. When  RFB = 10 K Ω and R_calibration = 33 K Ω used. The results are fine. But values are negative. Like, for unknown impedance of 50 K Ω, output displayed as  -50 K Ω. Negative values are displayed. Why like this ?

    2. And when I used R_cal values above that,  like, I used R_cal= 43  K Ω or 50 K Ω and anything above. 

    The results are displayed as  -22  K Ω  for every frequency in the entire frequency scan and same for any unknown impedance. 

    I am unable to resolve this problem. Please help me on this. 

  • I am using arduino-ad5933 code available on , https://github.com/mjmeli/arduino-ad5933.

    Do you use this code from the repository you indicated to print values?

    What are the settings you program into the chip: excitation voltage range, PGA gain, MCLK (external or internal?), frequency range, etc.?

    Debugging third-party code remotely is rather difficult, we can mostly look at the symptoms and guess. Can you export the printout into a text file and post it here through Insert->Image/video/file ?

    Particularly useful would be raw Re and Im data sets collected when:
    1. Nothing is connected in place of Z
    2. R_calibration is connected in place of Z
    3. "R_unknown" is connected in place of Z.  

  • Hello Snorlax!

    My board Connection was not appropriate. Now it is solved.

  • Hello ! 

    I have a question related to figure -1 in the datasheet of AD5933 IC and UG-364 user guide. 

    From VOUT to voltage Signal,  just  before GAIN block (inside the AD5933 block), what I understood is VOUT , observes an gain of RFB/Z_calibration. But still Vdd/2 appears along with the amplified sinusoidal signal .  Only thing is Vdd/2 or offset is not amplified. Is this correct ? Won't this Vdd/2 create problem or is it eliminated inside the chip ? 

  • Yes this is correct: the Vdd/2 is not getting amplified. The OPAMPs inside the AD5933 are also referenced to Vdd/2 internally, so this Vdd/2 DC voltage serves as the so-called virtual ground throughout both the external and internal circuits.

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