The N34C04 is a EEPROM Serial 4-Kb SPD for DDR4 DIMM, which implements the JEDEC JC42.4 (EE1004−v) Serial Presence Detect (SPD) specification for DDR4 DIMMs and supports the Standard (100 kHz), Fast (400 kHz) and Fast Plus (1 MHz) I2C protocols. One of the two available 2−Kb EEPROM banks (referred to as SPD pages in the EE1004−v specification) is activated for access at power−up. After power−up, banks can be switched via software command. Each of the four 1−Kb EEPROM blocks can be Write Protected by software command. *** The N34C04MU3ETG will respond with NoACK following the dummy Data Byte, while the N34C04MU3EKTG will respond with ACK by "SPD Page Select Command".