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USBLC6-2SC6 ESD wont protect

Question asked by Laszlo Nagy Kanasz on Aug 24, 2017
Latest reply on Aug 24, 2017 by Eugene Solo

Hi

We have a device which is an USB powered(USB2.0), and on the same USB port is the communication with the PC.

So it is powered from the PC.

For the ESD protection of the USB lines we add the USBLC6-2SC.

Our processor is a TIVA TM4C1294NCPDT type.

The device is continually streaming, the PC program only captures what the device is sending.

The problem is with the ESD events.

We tray in laboratory, and a 2kV ESD spike is enough to make problems.

As we see the device wont stops, nor even reset, so the ESD spike is not interrupting the streaming, but the PC detect a disconnect of the USB device, and after it connects back automatically...(but we have to restart our capturing program

every time)

Is this a specific problem related to our HW design, or the problem is with the ESD protection chip itself.. I read on some posts that this ESD TVS array is not the best for the cases when the VBUS status is detected... but our case is not that.. we does not pull off/on the USB plug, and the power line (VBUS) is working continually (we use some galvanic separation DC/DC to power our processor part from the VBUs line).

 

Is there some issues using this ESD protection ?

Should we use some other type, other methods?

Part of our USB power/communication schematics section is attached.

USBpower and comm part ESD protection

 

Best Regards

Laszlo

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