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ADS127L18: Devices can't work after running several days

Ryker She
Expert 4430 points
Part Number: ADS127L18
Other Parts Discussed in Thread: ADS127L21, ADS127L14, ADS127L11

Tool/software:

Hi expert,
My customer is testing ADS127L18 in project and they found the ADS127L18 can't work after it run several days in customer board. R&D confirm the power supply, reference, crystal all normal, but DCLK has no output. Do you have some suggestion to analyze this issue? Customer can't do the ABA test currently because of the PCB board limit. Thanks.
Best Regards,
Ryker

  • 0
    TI__Mastermind 46760 points

    Hello Ryker,

    Please confirm that the START pin and RESET pins on the ADS127L18 are at IOVDD voltage, 1.8V nominal.

    Verify the CLKIN pin is active clock.

    Can the customer get the ADC to work by power-cycling the board?

    If the device no longer works, then it may have been damaged by an EOS (electrical over-stress) event.  Please send an image of the schematic showing the ADC and input connections, including the input amplifier.

    Regards,
    Keith Nicholas
    Precision ADC Applications

  • 0 in reply to Keith Nicholas
    TI__Expert 4430 points

    Hi Keith,

    Customer has confirmed the START and RESET pins on the ADS127L18 are at IOVDD voltage, but they power the IOVDD with 3.3V (They have confirmed the 3.3V IOVDD is OK from TI team before).

    CLKIN is active clock.

    The device still can't work by power-cycling the board.

    The schematic as below show, please help to analyze.

  • 0 in reply to Ryker She
    TI__Mastermind 46760 points

    Hello Ryker,

    Not sure where the misunderstanding occurred, but the IOVDD is only rated for 1.95V maximum, and ABS MAX is 2.2V.  These are low voltage IO cells inside the device and cannot be operated greater than 1.95V for any extended period of time without permanent device damage.

    The customer will need to change their board design, provide 1.8V to IOVDD pins, and if necessary, use voltage level translation for all digital IO pins to meet the 1.8V logic level requirements.

    The single channel versions of this device, ADS127L11 and ADS127L21, use higher voltage IO cells which can support 3.3V, but not the multi-channel ADS127L14 and ADS127L18 devices.

    Regards,
    Keith