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How to design two AFE5809 for realize a doppler measurement with 16 piezo?

Hello

I want to design a Doppler circuit with two AFE5809s, and use 16 piezo elements to realize a Doppler measurement. The analogue to numerical conversion, is realize with an ADS8472 like the AFE5809 datasheet proposed (‘’CW Supporting Circuits’’ section). In attachment, you can find my proposed circuit (multiple AFE in application note).With this circuit; I have a couple of question.

1 :  Can you say me if my proposed circuit is good? And if is not can you give me the good one?

2 : If my circuit is ok, What is the routing constraints of the differentials pairs? Does the diff pairs of CW_IPAFE1_OUTM, CW_IPAFE1_OUTP, CW_IPAFE2_OUTM, CW_IPAFE2_OUTP, CW_QPAFE1_OUTM, CW_QPAFE1_OUTP, CW_QPAFE2_OUTM and CW_QPAFE2_OUTM must have the same lengths?

 

Finally, we have pay the AFE5809 dev board, can you say me if can i have the Gerber file or eventually the Altium, Cadence files...of this AFE5809 dev board? Can you send me one of them?

Best regards

Sam

  •  

    Sam,

    Your configuration is correct for the CW Voltage Output mode (Figure 103).  Also, see the Design database for the AFE5809 EVM here:

    https://txn.box.com/s/7exnwc5h9jf12cr49ojc2evpegzu5nda

    Do you still need the Gerbers?

    Thanks,

     

    Chuck

     

    Chuck Smyth, Applications Engineering, HealthTech-Imaging

    Please verify post if question is answered.

  • In reply to csmyth:

    Sam,
    About the routing constraints: Obviously each diff pair needs to be matched length. But also, all channels need to be matched length up to the common point. With CW doppler the phase is very important, so a little delay could result in lower SNR. Then, the phase between I and Q is also important so these lengths need to match as well.
    Chuck

    Chuck Smyth, Applications Engineering, HealthTech-Imaging

    Please verify post if question is answered.

  • In reply to csmyth:

    Hi Chuck
    Thanks a lot.
    Yes i want the GERBER file (i can read it without difficulty).
    For the Design database (AFE5809 EVM), can you say me what software can i use to read it.
    Best regards
    Sam

  • In reply to Samm:

    Sam,Here are the Gerbers:txn.box.com/.../e47uytxc8940oqifky6lmwjvtvl2kcuj
    The AFE5809EVM design was done in Mentor Graphics.Chuck

    Chuck Smyth, Applications Engineering, HealthTech-Imaging

    Please verify post if question is answered.

  • In reply to csmyth:

    Hi Chuck

    Thanks for the Gerbers file

    Sam

  • In reply to Samm:

    Hi Chuck,
    In attachment, you can find my final design. Before routing it, i want to confirm with you my design.

    For the values of R5,11,16,18,25,31,36 and finally R38, i chose these values equal to 499 Ohms. Does these values are good?

    Finally, on the ti website, i find the AFE5816. Can you say me more about it the price, datasheet, and eventually dev board.

    Thanks

    Sam

  • In reply to Samm:

    Sam,

    Please see the attachment for the CW Mixer Out external amplifier reference.  I recommend an external amp, but I have not tried going straight into the ADC.  In this case,  I believe the 500 ohm might be unnecessary.

    Thanks,

    Chuck

    CW Mixer Out from AFE5809_EVM_RevA_Sch.pdf

    Chuck Smyth, Applications Engineering, HealthTech-Imaging

    Please verify post if question is answered.

  • In reply to Samm:

    Sam,
    The info for the AFE5816 would require an NDA. If you are interested in that we could help set that up. Could please tell me more about your application and company, or if you want to take this offline, please attach your email address or you can friend me on e2e. The EVM is available.
    Chuck

    Chuck Smyth, Applications Engineering, HealthTech-Imaging

    Please verify post if question is answered.

  • In reply to csmyth:

    Dear Sam,

    Can you please provide me detailed datasheet for AFE5816 under NDA condition. I can email details about my application

    Best regards,

    Vassili

    vi@pst-inc.com

    http://www.pst-inc.com/

    Vassili Ivanov, PhD
    System Architect / CTO / co-founder
    PhotoSound Technologies, Inc

  • In reply to Vassili Ivanov40:

    Done.

    Chuck Smyth, Applications Engineering, HealthTech-Imaging

    Please verify post if question is answered.