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ads830 powering

Yossy Goldenberg
Prodigy 240 points
Other Parts Discussed in Thread: ADS830

hello,

I intend to use ads830 analog to digital converter in my design and I have a question regarding powering the device:

in my design, the VDRV supply pin is powered from a 3.3v power supply which is always on, and since there is no enable pin for the ADS830, I am considering to switch the VS power supply pin on, if i need to do measurements and off if measurements are not required. Can I do that without damaging or latching the device?

Please advise,
Yossy Goldenberg

  • 0
    TI__Guru* 91947 points

    Yossy,

    We are looking into this.

    Regards,

    Jim

  • 0 in reply to jim s
    TI__Mastermind 29220 points

    Hi,

    this is a very old device, one which came to TI by way of the Burr Brown acquisition years ago and the original designers have now all retired.  In most cases, all the information we have available is what is in the datasheet.

    I do see that the datasheet states that there is no internal connection between the VS and VDRV so that VDRV can be 5V or less.   There is no power sequence sequencing requirement listed either, so there would be no issue with VS being lower than VDRV, at least in the short term.

    But I also note that the absolute maximum ratings early in the datasheet require that the analog and digital input signals be less that VS + 0.3V.   so if you power down VS you  are supposed to power down signals that are driven *to* the ADS830.  Such as clock, analog input, and digital control pins.   Otherwise the ESD diodes can turn on and the device can try to power itself up from current drawn from the input signals and if these signals are not current limited then there would be no limit in the ADC as to how much current the device would try to pull from the input signals.   Usually violating this requirement short term on the debug bench is not an issue, but long-term it could affect reliability.  I would recommend not powering down VS unless you can also power down the inputs to the ADC.

    Regards,

    Richard P.