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  • TI Thinks Resolved

ADC12D1600: Regarding DNC pin

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Replies: 12

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Part Number: ADC12D1600

Hi

If DNC pin of ADC12D1600 is shorted to power rail or Ground? What will happen? Could you briefly explain?

Regards,

Aravindhan R

  • Guru 61550 points

    Aravindhan,

    We are looking into this.

    Regards,

    Jim

  • Guru 61550 points

    In reply to jim s:

    Aravindhan,

    The pins that may cause a problem if connected to power or GND is D7 and U7. The others probably will  not cause a problem.

    Regards,

    Jim

  • In reply to jim s:

    Hi Aravindhan,

    Depending on which pins are connected to Ground or power can have different effects.

    Can you please share what pins are connected and to what voltage level?

    Regards,

    Rob

     Rob Reeder

    Application Engineer

    High Speed Converter Group

    Texas Instruments Inc.

  • In reply to Rob Reeder:

    Hi Rob

    I want to know the effects when all DNC(D1,D7,E3,F4,W3,U7) pins get shorts to power or GND. The voltage level will be 1.9V.

    Regards,

    Aravindhan R

  • In reply to jim s:

    Hi Jim

    Could explain briefly why that particular pin have some problem and also why others doesn't cause? and also tell what functionality will get affected if that short to GND or Power.

    regards,

    Aravindhan R

  • In reply to Aravindhan Rajaganesan:

    Hi Aravindhan,

    D1, is probably okay, it has an internal pull-down or pull-up inside the IC.

    D7 and U7 are connected to circuits inside the IC. These are the most critical and should not be connected to PWR or GND.

    E3 and F4 are connected to circuits inside the IC. These are high-impedance. Not sure of the cause when connected directly to PWR or GND.

    W3 is connected to circuits inside the IC. Not sure of the cause when connected directly to PWR or GND.

    We feel it would be best to modify the PCB layout to remove these connections to PWR and GND altogether.

    Regards,

    Rob

     Rob Reeder

    Application Engineer

    High Speed Converter Group

    Texas Instruments Inc.

  • In reply to Rob Reeder:

    Hi Rob

    I need this information for doing FMEA in that I need to describe exact failures of IC. From your response,I can get idea that D7 and U7 are connected to internal circuits and those have severe effects when shorts to Pwr or GND. But I want to know the internal circuits for each DNC pin and also exact functional failures of IC when each DNC shorts to Pwr or GND. Your explanation will help me to know the exact functional failure. Kindly response

    Thanks and regards,

    Aravindhan R

  • In reply to Aravindhan Rajaganesan:

    Hi Aravindhan,

    Unfortunately, we just don't have that kind of information on forcibly trying to break a device in the lab and understanding the failures associated with connecting the recommended DNC pins to ground or power.

    It is advised that the board design be updated per the datasheet DNC pins outlined in the datasheet.

    Regards,

    Rob

     Rob Reeder

    Application Engineer

    High Speed Converter Group

    Texas Instruments Inc.

  • In reply to Rob Reeder:

    Hi Aravindhan,

    I have some additional information that came back from the design team today regarding pins D7 and U7.

    "Shorting high for even short periods may cause device failure. There is an ESD diode from these pins. If 2V forward bias on this ESD diode with no current compliance may cause the ESD diode to fail, permanently shorting the on-die generated negative charge-pump voltages to ground."

    Hopefully you find this helpful.

    Regards,

    Rob

     Rob Reeder

    Application Engineer

    High Speed Converter Group

    Texas Instruments Inc.

  • In reply to Rob Reeder:

    Hi Rob

    Yes this information is helpful. Could you get back further information from design team about the internal circuits for all DNC pins and exact failure modes?.

    Because I need these details to write failure cases in Failure mode analysis.

    Thanks and regards,

    Aravindhan 

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