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ADS1274: ADS1274 External Clock

P_I_D
Prodigy 170 points
Part Number: ADS1274

Hi

I have a question regrading the the CLK pin, can the adc work without any external clock source connected ?

  • 0
    TI__Mastermind 46550 points

    Hello,

    No, the ADS1274 requires an external clock for operation.  There is no internal clock inside the device.

    This clock source is typically generated by an external clock oscillator, with a nominal frequency of 27MHz to support data rates up to 105ksps.

    Regards,
    Keith Nicholas
    Precision ADC Applications

  • 0 in reply to Keith Nicholas
    Prodigy 130 points

    Hi,

    Can we use a 32MHz external clock instead of the 27MHz clock?

  • 0 in reply to Farouk A
    TI__Mastermind 46550 points

    Hello Farouk,

    Yes, the ADS1274 can be used with an external 32MHz oscillator.  Please note that SPI is not supported for clock frequencies greater than 27MHz.  If using a 32MHz clock frequency, you will need to use Frame Sync mode for communications.

    Also, when Fclk>27MHz, only High-speed mode is supported and the voltage reference is limited from 0.5V to 2.6V max.

    The output data rates will be proportional to the clock frequency.  If using Fclk=32MHz, then the output data rate (ODR) will be equal to:

    ODR=Fclk/256=32M/256=125Msps.

    Regards,
    Keith