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External clock source with ADS8413

Will Kim
Prodigy 40 points
Other Parts Discussed in Thread: ADS8413

ADS8413 is able to select internal clk or external clk.

I'm curious that what if I source under 200MHz ext clk, like 100MHz or etc. does it make work slowly or doesn't?

Actually I got this info form another question. please refer About ADS8413

For the more, If I supply low frequency of external clock, does it course to change timing (Tw1, Td1...) 

  • 0
    TI__Guru 55466 points

    Hello Will,

    Sourcing external 100MHz (or slower) may limit the throughput and sampling rate that will be supported; i will verify with the design group.

    It appears from the previous post that you are planning to use the device on the Daisy Chain mode; How many devices are you planning to connect and what is the maximum sampling rate required in the application? 

    Thank you and Best Regards,

    Luis

  • 0 in reply to Luis Chioye
    TI__Guru 55466 points

    Hello Will,

    The product can be driven with an external clock of 100MHz.  If the device is driven with a clock of 100 MHz, the conversion time is not affected; and the pulse duration for CSTART/CONVST and required td required delays are not affected; (except for td12, td13, td15 as indicated on the datasheet).  Conversion time is not affected with different serial clock frequency as conversion is always running using internal oscillator clock. However, the external 100MHz (or slower) may limit the throughput and therefore the sampling rate that will be supported depending on the number of devices on the Daisy Chain.

    The "Timing Diagrams For Daisy Chain Operation" from page 15 of the datasheet (also shown on the post above) relates the conversion speed to the number of devices on the Daisy Chain for a given serial clock frequency. 

    Thank you and Best Regards,

    Luis