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TPD4E001: ESD Selection Recommendations

Kelly Li2
Prodigy 210 points
Part Number: TPD4E001


Tool/software:

Hi All,

Happy new Year！

Due to the previous generation IC‘ EOL, the new one with ESD immunity downgrade from HBM 4Kv, MM 200v , CDM 750V/500V to ESD HBM 2Kv, CDM 500V.

After using the new one, we encountered device failure after assembly process.

in order to solve this issue, we chose ESD protection IC, the situation has improved, but not completely solved.

the SCH as following

the PN of ESD is CESD5V0L4

CESD5V0L4.PDF

let me explain our assembly process in detail

Wrapped in epoxy resin glue PCBA--1, through the ABS material tube-2, in the process there will be a chip on PCB damage, would you please help to recommend a TI suitable ESD chip can be as far as possible to solve this issue？

Many thanks

BR

Kelly

  • 0
    TI__Expert 8750 points

    Hi Kelly, 

    Happy New Year! 

    Based on the operating voltage of the IC (SHT40), a protection diode with a 3.6V working voltage will be needed. If you are open to switching the package, I would recommend our ESDS302 device. It is a 2-channel device in SOT-23 and has 30kV ESD protection. 

    I believe the reason why failures are still occurring is because the current ESD diode has a higher working voltage which in turn means the clamping voltage is higher and is not protecting the downstream IC. 

    Please let me know if you have any questions.

    Best,

    McKenzie

  • 0 in reply to McKenzie Eaker
    Prodigy 210 points

    Hi McKenzie,

      thank you so  much for your quick reply!

    changing the package is acceptable, but i need to make sure the dimensions are OK, as shown in the picture the size of the PCBA is limited by the inner diameter of the tube. if there is the same function when the size is smaller it is also very welcome. i will evaluate the possibility of SOT23 today.

    there is  a question to be confirmed. During assembly, the connection wires corresponding to the 4 pins of VCC/GND/SDA/SCL are float status, not connected, will this affect the ESD302 protection effect?

    many thanks.

    BR

    Kelly

  • 0 in reply to Kelly Li2
    TI__Expert 8750 points

    Hi Kelly, 

    Please let me know if SOT23 isn't suitable and I can find a different option in a smaller package. 

    So the protection device won't protect the IC unless it is connected. The ICs ESD HBM and ESD CDM should be high enough to survive manufacturing and assembly, so if it isn't, then I would recommend reaching out to the company that makes the device. 

    Best,

    McKenzie

  • 0 in reply to McKenzie Eaker
    Prodigy 210 points

    Hi McKenzie,

    the room is OK for SOT23.

    But now it looks like the big issue is that we couldn't make sure the IC pins are connected when manufacturing and assembly.

    If we couldn't make sure be connected, is there a solution other than reaching out to the manufacturer?

    many thanks.

    BR

    Kelly

  • 0 in reply to Kelly Li2
    TI__Expert 8750 points

    Hi Kelly, 

    The only other solution is to make sure basic ESD control is being used. This means wrist straps, grounded work surfaces, and safe packaging materials. 

    Best,

    McKenzie

  • 0 in reply to McKenzie Eaker
    Prodigy 210 points

    Hi McKenzie,

    thanks very much for your suggestions.

    The methods mentioned in the picture that we all already used, but there is a problem here, the static electricity generated inside the ABS tubes can't be conducted out, this could lead to chip damage.
    It seems that we have to go for higher ESD HBM and ESD CDM devices.

    many thanks.

    BR

    Kelly