AD9635 power-up time

Hi,

which is time needed to have the AD9635 up and running after power supply has been applied?

I'm not sure I can consider the value indicated for the "Wake-Up Time (Power-Down)" stated in the datasheet.

thanks

Regards,

Alberto

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  • +1
    •  Analog Employees 
    on Apr 2, 2019 3:59 PM

    Hi Alberto,

    Yes, you are correct. The 375us wake-up time from power down is the time to wake-up from the power-down mode, and not from initially bringing up the power supplies.

    When first powered up (and also after a Register 0x08 Digital Reset), the AD9635 goes through an initialization sequence. This sequence takes about 3 million sample clock cycles. This process starts after the analog is up.

    At a sample clock frequency of 125MHz, 3 million clock cycles takes about 24ms. If we say that the analog take about 1ms to come up (375us + fudge factor), this gives us 25ms. So, conservatively let's say that 40ms is needed.

    A lower sample rate will obviously increase the time required.

    Thank you.

    Doug

Reply
  • +1
    •  Analog Employees 
    on Apr 2, 2019 3:59 PM

    Hi Alberto,

    Yes, you are correct. The 375us wake-up time from power down is the time to wake-up from the power-down mode, and not from initially bringing up the power supplies.

    When first powered up (and also after a Register 0x08 Digital Reset), the AD9635 goes through an initialization sequence. This sequence takes about 3 million sample clock cycles. This process starts after the analog is up.

    At a sample clock frequency of 125MHz, 3 million clock cycles takes about 24ms. If we say that the analog take about 1ms to come up (375us + fudge factor), this gives us 25ms. So, conservatively let's say that 40ms is needed.

    A lower sample rate will obviously increase the time required.

    Thank you.

    Doug

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