This application note discusses operation of Teridian's 71M6531–71M6534 energy-metering system-on-chip (SoC) devices with external serial SRAM. The SRAM can be an extra storage space outside the SoC, thus extending the IC's internal 4KB XRAM. SRAM components can also be used with shadow RAM capabilities, like the FM25H20. This Ramtron® device automatically transfers RAM contents to a non-volatile memory portion on- chip when the power supply is lost. As a result, there is no microprocessor (MPU) involvement to save billing and other data when the meter's main voltage is lost.