• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 15 subscribers
  • Views 311 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

ISO3082: ISO3082DWR: About ESD protection.

cyan zhou
Expert 1500 points
Part Number: ISO3082
Other Parts Discussed in Thread: ISO1410

Hi TI Expert,

Please help to guide the following consultation on ESD protection:

1.  According to the datasheet, the ELECTROSTATIC voltage of HBM is ± 16kV, which refers to Between Bus Pins and GND2.

Why is it so defined? The antistatic generally refers to PE(protecting earthing).  Is it necessary to add protection to PE?

2. Contact 8kV and air discharge 15kV are our test requirements for communication ports. Is it necessary to add protective circuit outside? If so, how should it be added?Please guide me. Thank you.

Cyan

  • 0
    TI__Mastermind 49445 points

    Hi Cyan,

    The ESD protection that you are seeing in ISO3082 datasheet is HBM ESD which is different from IEC 61000-4-2 ESD. HBM ESD protection in device is meant to protect it from any ESD events that can happen during device handling in an ESD controlled environment. This means that HBM ESD protection is only meant for protecting device when the device is going to be assembled on the PCB for the first time in an assembly site.

    IEC 61000-4-2 is a different ESD standard which applies to end equipments and is not defined to individual components / ICs. Hence, the test refers to Protective Earth (PE) and not to device individual pins.

    Based on how ISO3082 is used in an end equipment and how ESD testing is done (which can be different for different end equipment), the actual ESD pass levels at the equipment can be different. It also depends on what external protections used against ESD.

    Most commonly, ESD is applied on the external terminals of an equipment and since RS-485 bus is going to be on the external terminals, it will be stressed. Some customers might test RS-485 bus with respect to the local GND while others might test it with respect to PE which is on the other side of isolation barrier. Some customers might test it for both case, it all depends on end equipment, end customer and standards to be tested.

    To be able to support 8kV contact and 15kV air on both RS-485 bus and also across the isolation barrier, we recommend customer to use ISO1410. This device has been guaranteed to support 8kV on both RS-485 bus and also across the barrier as mentioned in the datasheet (also shown below).

    Regards,
    Koteshwar Rao