The VBUS054CD-FHI is a four-line ESD-protection device with the characteristic of a Z-diode with a high ESD-immunity and a very low capacitance which makes it usable for high frequency applications like USB2.0 or HDMI.
With the VBUS054CD-FHI four high speed data lines can be protected against transient voltage signals like ESD (Electro Static Discharge). Connected to the data line (pin 1, 2 and pin 4, 5) and to ground (pin 3, 8 and 11) negative transients will be clamped close below the ground level while positive transients will be clamped close above the 5 V working range. The clamping behaviour of the VBUS054CD-FHI is bidirectional but asymmetrical (BiAs) and so it offers the best protection for applications running up to 5 V.
Modern digital transmission lines can be clocked up to 480 Mbit/s (USB2.0) or 1.65 Gbit/s (HDMI). At such high data rates the transmission lines like cables or the line traces on the PCBs have to be very homogeneous regarding their surge impedance. This requires well defined trace dimensions as trace width and distance which have to be calculated depending on the requested surge impedance (e.g. 50 ohm) and the PCB material and layer dimensions. Any device connected to the data lines - like ESD-protection devices - have to be connected with minimal changes in these trace dimensions and distances.
With the package in the so called “Flow Through Design” this is possible. The lines are running straight along the PCB while the VBUS054CD-FHI is placed on top without any vias or loops.