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ADC08D500: ADC08D500

user3756530
Intellectual 940 points
Part Number: ADC08D500

When we used ADC chip ADC08D500, we found that the output of ADC chip had burr and the working temperature was very high. The surface temperature was measured at 70℃ with an infrared thermometer.

After many measurements, the conclusion is as follows:

There is no burr in the ADC output when the power is turned on at low temperature. In the case of constant power supply, even if the subsequent temperature rise will not affect the ADC output.

In a high temperature environment, ADC output burr, the higher the temperature, the more burr, the subsequent use of fans to reduce the temperature can not make the ADC output better.

I would like to ask you what is the reason for this situation?Looking forward to your reply!

  • 0
    TI__Mastermind 35330 points

    Hi,

    Please define "ADC output burr" for me?

    Is this a TI EVM or is the ADC mounted on your own board design?

    Regards,

    Rob

  • 0 in reply to user3756530
    TI__Mastermind 35330 points

    Hi Peng,

    It is possible the part is not solder down to the PCB correctly?

    Are all of the power supplies working properly?

    Can you check the clock coming into the ADC, is it the correct amplitude and level?

    You could try removing these components, they shouldn't be needed.

    Regards,

    Rob

  • 0 in reply to Rob Reeder
    Intellectual 940 points

    About what your said, I check the PCB connect 、the power supplies 、the clock of ADC08D500, 
    all of them is normal and i I configured the peripheral circuit of the chip according to the instructions in the DataSheet.
    It is naomal working when low temperature start. When it start in high temperature, it waveform is as attached.
    Looking forward your reply!

  • 0 in reply to user3756530
    TI__Mastermind 35330 points

    Hi Peng,

    Is the oscope capture the clock inputs? Not sure what I am looking at?

    If the part is working at the start, when you turn this on and the temperature is low, then stops working when the temperature is higher and the part has warmed up. This make me believe the ADC is not properly soldered to the board.

    You could try putting pressure on the ADC part itself to hopefully make better connection. 

    Thanks,

    Rob

  • 0 in reply to Rob Reeder
    Intellectual 940 points

    I understand that what you said，I recheck the PCB connect,it is OK.As for the circuit near the crystal oscillator mentioned in your email,

    That is the standard circuit from LVPECL to LVDS level recommended in the DataSheet.And I found that there is no power on calibration and command calibration in the program,

    Whether this will cause problems with the output when the temperature rises?Looking forword your reply.

  • 0 in reply to user3756530
    TI__Mastermind 35330 points

    Hi Peng,

    In order to change from LVPECL to LVDS, you will need a translator buffer IC, I am locating one for you if we have one.

    Otherwise, I know On Semiconductor has many of these devices to offer.

    You should still be able to capture appropriate data without a calibration. However, you can try calibrating the device and see if you get an improvements.

    Is it possible to share some data captures/FFT plots or time domain plots?

    Would it be possible to share your schematics?

    Regards,

    Rob

  • 0 in reply to Rob Reeder
    TI__Mastermind 35330 points

    Hi Peng,

    For a LVPECL to LVDS buffer please review the SN65LVDS100D single buffer to start.

    We have a whole portfolio of devices that have a wide common mode input voltage range that start with SN65LVDS.

    Hope that helps.

    Regards,

    Rob