64 Kbit I2C EEPROM — what the 450 ns access and 1 MHz bus clock mean for your design
The STMicroelectronics M24C64-WMN6P is a 64 Kbit serial EEPROM organized as 8K x 8 bits, accessed over an I2C bus at up to 1 MHz. The 450 ns access time is the random-read cycle — the time from the address byte to the first data byte appearing on SDA. For a host controller polling the bus, that 450 ns window sets the minimum SCL high time before sampling; the part itself does not stretch the clock, so the master must hold SCL stable for the full access window or risk reading stale data. The 5 ms write cycle time is the page-write duration — the bus is held busy during that interval, so the host must either poll the acknowledge polling sequence or insert a delay before the next write.
NRND — not for new designs, but still a valid BOM line for existing production
That means STMicroelectronics still manufactures it for existing customers, but no new design-ins should target this order code. For a production BOM already qualified on this part, the NRND flag is a signal to plan a migration — not an immediate crisis.
8-SOIC package — rework-friendly footprint for hand assembly or reflow
The lead pitch is 1.27 mm — wide enough for a standard chisel tip or hot-air nozzle without bridging. The body sits low enough that underfill is not required for typical industrial temperature cycling.