The 34AA04 4-kbyte I2C serial presence detect (SPD) EEPROM is designed to work with next-generation Double Data Rate 4 (DDR4) SDRAM modules used in high-speed PCs and laptops. Developed by Microchip, the JEDEC JC42.4 SPD-compliant device operates from 1.7 to 3.6 V. It includes reversible software write protection for each of four independent 128- by 8-bit blocks, and supports a new SMBus-compatible bus time out. Other features include page write capability of up to 16 bytes of data, and three address pins that allow up to eight devices on the same bus. The 34AA04 is backward-compatible with existing DDR2/3 SPD EEPROMs. Its memory array is divided into two separate 256-byte banks to overlay with the architecture of older SPD EEPROM devices. Packaging options include an 8-pin SOIC, TDFN, UDFN, TSSOP, and PDIP.