Serial EEPROMs STMicroelectronics Serial EEPROMs offer I2C (M24 Series), SPI (M95 Series), and Application Specific (M34 Series) bus types to meet a wide variety of design application requirements. These devices include the industry's largest memory size (2Mb), smallest standard package (UFDFPN5), smallest and ultra-thin WLCSP packages, and a guarantee of up to 4 million erase/write cycles and 200 years data retention.