The STMicroelectronics M24C01-WBN6 is a 1Kbit serial EEPROM organized as 128 x 8 bits, communicating over an I²C bus at up to 400 kHz.
900 ns access time — timing margin for the I²C bus
The 900 ns access time is the window from a valid address match to data appearing on the bus. At 400 kHz I²C, that 900 ns leaves margin for the rest of the bus transaction.
The M24C01-WBN6 is officially listed as obsolete by STMicroelectronics.
Pin-compatible replacement planning
The M24C01 family shares the same I²C interface, 1Kbit density, and 8-pin DIP footprint across density variants. For a new design or a BOM refresh, a current-production I²C EEPROM in the same 8-DIP package from ST or a second-source vendor would be the natural cross-shop — same pinout, same supply range, same bus speed.