ESD_protection for data lines.

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We are interested in protecting the communication data lines (CAN / RS485 communication lines) connected to an Automotive grade industrial connector. The pins connecting this connector are driven by a 3.3V typical operating condition.

1. What are the critical criteria for protecting my device from ESD?
2. How Important is the capacitance of the TVS diode/ESD?
3. Should we select a TVS diode depending on its Rated Working Peak Voltage and clamping voltage?
4. ESD contact level - (air and contact)
5. What is the role of Peak Impulse Current on selecting a ESD/ TVS diode?
6. Criteria for ESD on a power line ?
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Sergey_Karpov
Employee
Employee
Hello Zaid,

Thank you for your interest in our products. I will try to give you answers on your questions.

1) One of the critical aspects of protecting your Device is an injection point of ESD Strikes. How do ESD Strikes reach your data lines? (Device assembly, Operation by end-User or through other interfaces)

2) For High-Speed-Communiction standards such as USB2.0/3.0/HDMI/eSATA and other applications where operating frequency lies in GHz area, capacitance of TVS devices play a very important role. The TVS Diode connected in parallel to the Signal line builds a low-pass filter whose cut-off frequency is determined by the capacitance value of the TVS Diode.

3) A customer should select a TVS Diode according on the working voltage of his application and the clamping voltage of the TVS device. Meaning the TVS Diode must become conducting very fast when the maximum operating voltage of the device is exceeded.

4) Both types of this ESD discharges may cause malfunction and the destruction of the device during device assembly and its usage.

5,6) If there is a requirement that the device must sustain a 15KV ESD contact discharge (corresponding to 30A ESD current), the important aspect is at which clamping voltage a TVS device conducts 30A. This value of the clamping voltage must lie near to the working voltage of the device.

I hope this will help you in the right selectiong of the TVS Device.
On our product page you can select the right Diode according on ist working voltage / capacitance value / package size.

http://www.infineon.com/cms/en/product/channel.html?channel=db3a304336ca04c9013702601bb62322#goto_pr...

For you application our ESD207-B1-02EL would be the right choice:

http://www.infineon.com/cms/en/product/esd-and-emi/multi-purpose-esd-devices/ESD207-B1-02EL/productT...

Description:


Ultra Low Clamping Bidirectional ESD / Transient Protection Diode

Summary of Features:

ESD / transient protection according to:
– IEC61000-4-2 (ESD): ±30 kV (air/contact discharge)
- IEC61000-4-4 (EFT): 40 A (5/50 ns)
– IEC61000-4-5 (Surge): 8A (8/20 µs)
Bi-directional, working voltage up to VRWM = ±3.3 V max.
Low capacitance: CL = 14 pF (typical)
Ultra low dynamic resistance: RDYN = 0.13 Ω typ.
Low reverse current. IR = 50nA (max.)
Pb-free (RoHS compliant) and halogen free package
see all
Target Applications:

Keypad, touchpad, buttons, convenience keys
LCD displays, Camera, audio lines, mobile communication, Consumer products (E-Book, MP3, DVD, DSC...)
Notebooks tablets and desktop computers and their peripherals


Best Regards,
Sergey Karpov
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