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ADS1218: Return from PWDN timing

Paul Mayer
Intellectual 380 points
Part Number: ADS1218
Other Parts Discussed in Thread: ADS1243

We are using the ADS1218 (and the ADS1243) in both chips there is a /PWDN pin that we use to shut down the part to conserve power.  My question is how long after raising /PWDN is the chip ready to use?  There doesn't seem to be a specification for this in the data sheet.

Thank you.

Paul Mayer

  • 0
    TI__Guru** 113765 points

    Hi Paul,

    Good to hear from you!  As the circuitry for both the analog and digital sections are powered down, you essentially have a POR startup period which would require internal circuitry to settle after the oscillator restarts.  Oscillator time may vary across temperature.

    For the ADS1218 (which I would believe would be similar for the ADS1243 as the device process is the same for both) has a RESET time of a minimum of 2640 tosc periods to complete (see the timing table on page 9 of the datasheet).  When using the 2.4576MHz crystal you would need to wait around this same time period which would be 1.08 ms minimum after oscillator startup.

    This is the best information I can give you as this was not characterized for the devices in question.

    Best regards,

    Bob B