G.fast Line Driver Protection Circuit
Created: Apr 11, 2016
No description available.
The demand of faster internet speed is common in which ISPs or Internet Service Providers are making a lot of investment in fiber technology. The present VDSL2 or Very high speed Digital Subscriber Loop 2 provides an internet connection speed around 80Mbps for download and 20Mbps for upload. In G.fast technology, the target internet speed performance is 1Gbps over 100m single twisted pair (24AWG/0.5mm) cable using DSL-like technology. It is new digital subscriber line (DSL) standard that works by increasing the frequency range used by broadband signals while amplitude is becoming very low compared to existing DSL that results in imperceptible capacitance variance of the overvoltage protection (OVP) component. Provided in this design, a new protective device for overvoltage with minimal effect on data signals in G.fast and some DSL variant applications.
The design is provided with some filters of frequency using resistors, capacitors, and fixed inductors. The filter side (particularly the LC filter) brings the signal with minimal noise in which the fequency filter provided has 30MHz+ resonant frequency requirement suitable to VDSL2 and G.fast applications. It is followed by DSLP0120T023G6RP component for overvoltage protection with ultra low capacitance characteristic. It provides low insertion loss and less distortion in higher data rates signals. It make use of flow-through pin assignment and layout that reduces impedance mismatching “stub effect” caused by non-”flow through” PCB trace connections and provides for an easier PCB design. There is no fusing requirements for power fault protection since it is capacitively coupled but the selection of voltage rated capacitors should be considered because of lightning exposure risks.
The design is suitable for G.fast, VDSL2, ADSL2, and ADSL2+ with slight modification like replacement of LC filters that correspond to the required frequency. It also applicable to some digital interface such as HD-SDI and HD-CVBS. This protective device can help in the development of G.fast standard.