The next section of this module will look at the various protection components available from Littelfuse that are frequently used in Ethernet protection designs. The SP3003 ESD protector is a light-duty device with a 2.5A surge rating suitable for those “2 meter” designs where a minimal amount of protection is required. It is available in either 1-pair or 2-pair protection configurations. The SP3050 ESD protector is the big brother to the SP3003. It is a medium-duty design with an 8 amp surge rating that can handle significantly more energy. The 2-Pair version can even be wired to double its surge capability to 16A for a single pair. The SP03-3.3, rated at 150A, is a Littelfuse protection device that has excellent surge handling capability. These are used in some of the more exposed Ethernet designs, with special considerations for Gig-E designs, especially at elevated temperatures as their capacitance nonlinearity becomes an issue. The SEP (silicon Ethernet protector) series were designed specifically for these emerging Ethernet applications. This series uses Littelfuse’s patented “biased bridge” technology to produce a semiconductor protector with almost no capacitance linearity issues. By applying a bias voltage to the protector, the semiconductor element is “preloaded” to minimize the absolute capacitance and practically eliminate the effect of line voltage on the capacitance of the device. The SEP is available in an 8V version which is suitable for the non-PoE applications and in higher voltages that fit into a range of PoE schemes. With a surge capability exceeding 400 amps, this is the only semiconductor protector capable of passing GR-1089 inter-building requirements without adding series resistance. Another advantage is that the footprint on the PC Board for the SEP is no larger than the SP03-3.3. The Enhanced TeleLink® Fuse is necessary to pass GR-1089 Inter-building requirements. It was specially developed to coordinate with the SEP series to provide full compliance without the use of other components. It is differentiated from the standard TeleLink® Fuse by its rating that assures it will open the circuit during the first five minutes of the 2.2A power cross test. This assures an uneventful clearing of the circuit – usually in the first minute.