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AFE7903: TX DSA Calibration

Christian Ryffel
Prodigy 150 points
Part Number: AFE7903
Other Parts Discussed in Thread: AFE7900

Tool/software:

Hi
We currently do not really understand the configuration for tx dsa calibration for the AFE7903.
"AFE79xx_TxDSACalibrationProcedure_Jun132019" talks about an external loopback from DAC to the feedback adc. Now, the AFE7903 has no feedback ADC, can we just connect to RX Channel 1(A) or 2(B)?
How is the txdsa routine in the cafe api to be understood?
afeInst AFE ID
    @param txChainForCalib Bit Wise TX Channel Select.<br>
            Bit0 for TXA<br>
            Bit1 for TXB<br>
            Bit2 for TXC<br>
            Bit3 for TXD
    @param txDsaCalibMode DSA Calibration Mode.<br>0 -Single Fb Mode FB AB ; 1 -Single Fb Mode FB CD ; 2- Dual Fb_Mode
    @param txDsaBandCalibMode Sets the TX DSA Band Calibration Mode.<br>

 

When we want to calibrate TXC and connect it externaly to RX A, what do we select in the cafe api call? The parameter description does not mention the RX A channel only the Feedback ADCs.
How should we configure the same for TX D and RX C?

  • 0
    TI__Expert 7815 points

    Hi Christian, 

    We had discussed this issue in today's meeting and concluded that using the TX DSA calibration will not help resolve spurs at the NCO frequency. I'll go ahead and close this thread for now, and we can create a new thread to discuss TX spur issues.

    As an FYI: generally, the TX DSA is quite accurate and does not require calibration, as the only source of error would be the matching network. Please see below for a graph of the TX DSA DNL error I measured on AFE7900 EVM; as you can see, the TX DSA has very low error.

    Thanks,

    Aman