Clamping voltage still dangerous to my MCU?

[Aldo_Flores_Aguayo]

Hi, I´m trying to implement ESD protection to a custom board, I found recommendations for this part number (USBLC6-2SC6), which clamping voltage is as follows 

Look at VCL Clamping Voltage  there are 12V and 17 V 

 

Then the USB pins of my MCU accept a maximum voltage of 5.5V so the 12V and 17V clamping voltage are not below maximum voltage of the USB pins of my MCU, doesn´t this clamping voltage still damages my MCU? and why this part number is recommeded for the ESD USB application??

And finally why In the imagen below is shows D+in and D+out as well as D-in and D-out ? It is the same line or not? How should I connect data lines to the IC? 

 

 

Hope you can help me it´s my first USB implementation using ESD, thanks for read! 

 

[FBL]

Hi @Aldo_Flores_Aguayo 

Clamping voltage is transient voltage during an ESD pulse, not a continuous voltage. It’s expected to be higher than the MCU max voltage (5.5 V) because the device only clamps fast high-current spikes, protecting the MCU from much higher voltages. So, it is recommended for USB because it has low capacitance (preserving signal integrity) and fast response to ESD events, and overall protection characteristics are met. Additional EMI common mode filter might be needed for USB HS applications. For example, typically, this USBLC6-2SC6 is suitable for USB FS host applications and should be placed as close as possible to the USB connector to ensure effective protection.

About your second point, D+ in /D+ out and D-in /D- out are the device’s input/output pins for each USB data line. You connect the USB connector side to the “in” pins and the MCU USB pins to the “out” pins, so the protection device sits in between in series and clamps ESD pulses before they reach the MCU.