Most SIDACtor devices use a very straightforward part numbering format. After the letter P, the following three numerical digits are a nominal breakdown voltage. For voltages less than 100V, there will be leading zeros. For example, an 8V part will have “0 0 8” as the three number code. Next comes the construction variable. Usually this is the number of chips actually contained in the device. A number one in this position indicates that this device has the reverse polarity diode found in the SLIC protection devices. The next position is a letter that defines the package used. One exception is that QFN devices will have the letter Q followed by two numerical digits. After that is the general surge rating. “A” rated devices are suitable for most European and Chinese telecom applications as they are usually paired with PTC devices for overcurrent protection. “B” rated devices are often used in customer premises equipment. These devices are designed to meet the TIA-968-A requirements. “C” rated devices comply with GR-1089 interbuilding standards. This is a key North American requirement for telephone company equipment. “D” and “E” rated devices are premium surge capable options for special applications where GR-1089 is not enough. Littelfuse has only a handful of competitors at the “D” level and no real competition at the “E” level. Back to the part numbering scheme, an “L” after the package designator indicates ROHS compliance. Finally the part number may have lead forming options or packing option suffixes.