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ADS1256: SCLK max period

Part Number: ADS1256
Other Parts Discussed in Thread: ADS124S08

Hi ,

From the spec , the minimun SCLK period - tc(SC) = 100 ns  ... but what is the max period or the lowest frequency SCLK the device can support ? 

Can it be 25 ns ? 4 times slower


  • Hi Cyril,

    The max SCLK period is defined as 4*(1/fCLK), or four times slower than the fCLK frequency. So if you choose fCLK = 10 MHz (the max fCLK frequency), then the max SCLK is 2.5 MHz. At the nominal fCLK frequency of 7.68 MHz, SCLK (max) can be 1.92 MHz.

    Is there a specific frequency you wanted the ADC to run at? I am a bit confused by your question since it seems like you want SCLK to run faster than the ADC?


  • Hi,

    I have made mistake in the title of the  ... I wanted to say ADS124S08 SCLK Max period ...

    So as I initiallly wanted to say:

    From the ADS124S08 spec , the minimun SCLK period - tc(SC) = 100 ns and with the internal fCLK of 4.096 MHz

    what is the max period or the lowest frequency SCLK the device can support ?  Can SCLK period be 25 ns ? or 4 times slower tan the spec 

    I am sorry for the mistake but I hope this is clear ... You can edit the title and make the correction



  • Hi Cyril,

    Thanks for clarifying.

    However, running SCLK at 25ns (25MHz) would violate the timing requirements, since the minimum SCLK period is 100 ns (10MHz). In other words, this would be operating the SCLK at a higher frequency (or faster) than is allowed. Are you asking if you could run it slower e.g. 400 ns, or 2.5MHz?

    The short answer is yes, it can run slower. But I am not sure what the absolute maximum speed would be e.g. can it run at 1kHz SCLK speed? I can look into this for you, though if you just want to know if you can run the SCLK at 2.5MHz, then the answer is yes.