This application note describes the features of Teridian's 71M6543F/71M6543G/71M6543H polyphase energy-metering SoCs. Most features will also apply to the single-phase 71M6541D/71M6541F. The 71M6543F/71M6543G/71M6543H include differential analog inputs, a fourth current input, enhanced clock system, battery modes, and 64KB flash memory space. However, several other features make these ICs powerful solutions for any polyphase meter. These enhancements can be categorized as functional, parametric, and packaging-related, and they will be briefly explained in this document.