To begin the design process, some parameters must be decided upon; the designer should make sure:

• Voltage range on the protected lines must not go beyond one forward diode drop above the V_CC and must no go below one forward diode drop below the ground.
• Operating frequency is supported by the IO capacitance C_IO.
• IEC 61000-4-2 protection requirement is covered by the IEC performance of the TVS diode.

For this application, a high speed USB 2.0 signal that ranges from –10 mV to 440 mV will be applied to each line. Connect a 5 V power supply to V_CC pin; therefore, the signal will not fall outside of the normal operation range and the TPD2S017 will stay passive and low leakage during normal operation.

Next, consider the data rate of this signal and ensure that the TVS I/O capacitance will not distort this signal by filtering it. The speed of a USB 2.0 high-speed signal is 480 Mbit/s. With TPD2S017's ultra low IO capacitance, this device can support 1.5 Gbit/s data rate and thus can pass USB 2.0 high-speed signal with minimal distortion.

Finally, TPD2S017 is rated for the IEC 61000-4-2 (Level 4) so it provides sufficient system-level ESD protection to the human interface in this application. See Section 10.2 for instructions on properly laying out TPD2S017.