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Original question:

ADS1278: ADC draws a lot of current when connecting IOVDD pins

ADS1278-SP: maximum allowable ESD diode protection current

SU ZHANG
Prodigy 210 points
Part Number: ADS1278-SP

We have a power-up situation where the IO signals will temporarily turn on for appx 2ms when the DVDD/IOVDD/AVDD are not up yet. Each IO signal is limited to less than 0.5mA current during the 2ms start up period. unfortunately, this will likely turn on the ESD protection diodes on the IO lines which is not ideal. We're trying to assess the risk of part damage under such condition. 

Do we know the maximum allowable ESD diode protection current limit for such a short period of time? What is the total amount of energy observed in your ESD test? thanks. 

  • 0
    TI__Mastermind 43800 points

    Hello Su,

    The ESD current limits during power-up can be found in the ABS MAX tables. Maximum continuous current is limited to 10mA.

    These power-up conditions will not damage or reduce the life of the part.  However, these conditions may cause incorrect power-up reset of the device.  In this case, you will need to assert the /SYNC pin after the power supplies have stabilized and data first appear (/DRDY goes low for first data ready).

    ADS1278-SP - is classified as 1C for ESD HBM.  A conservative value for ESD is 1000V using HBM model.

    Class 1C, 1,000 volts to 1,999 volts, per Method 3015 of MIL-STD-883G.

    Regards,
    Keith Nicholas
    Precision ADC Applications