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ADS131M04: Use single clock to synch 13x ADS131M04

Part Number: ADS131M04

Hello, i would like to use a single clock to synch all of my 13 ADS131M04. 

on the dev board, it use the clock SIT8924BA-22-33E-8.192000. 

As the dev board i put an RC filter of 51ohm with 10pF. I think i might have some rebond or something like that, but it's hard to evaluate with an oscilloscope because i'm adding a cap with my probe.

What would be your recommendation to use 1x SIT8924BA-22-33E-8.192000, to clock 13x ADS131M04? Do i need a buffer ? maybe the load on the clock pin is too high to drive 13 ADS?

thanks you for your help,

  • Hi Amaury,

    The more ADCs and the longer trace, the higher load for the oscillator. The capacitance load will affect the rise and fall time of the output clock from the oscillator. Try to minimize the capacitance load including the clock traces on your layout, and you may consider to use a drive strength of the oscillator if needed. See the following table about Rise/Fall time vs. Cload from SIT8924B datasheet.

    Regards,

    Dale

  • Hello Dale,

    thanks you for the answer! Unfortunately i have long trace on my layout. But tried to add trigger Schmitt gate (74LVC1G17W5-7) on the output and it look like it's better. What do you think about it? It is directly connected on the output of the clock. This shall deliver more drive for all ADCs right?

    thanks you

  • Hi Amaury,

    It's hard to say yes or no because it's really related to your board and design. Have you seen any issue of ADC's operation and data reading?

    Regards,

    Dale