64 Kbit I²C EEPROM for low-voltage buses
The Microchip 24CW640T-I/ST is a 64 Kbit serial EEPROM with an I²C interface, clocked at 1 MHz and organized as 8K x 8 bits. Its supply voltage range of 1.6V to 5.5V covers the 1.8V, 2.5V, 3.3V, and 5V logic rails you find on mixed-voltage boards — no separate level translator needed for the memory bus. The 450 ns access time is fast enough for most MCU reads without wait states, and the 5 ms write cycle (word or page) is the standard for this density class.
Surface-mount only, so plan for a standard SMD pick-and-place.
Microchip lists the 24CW640T-I/ST as an active product.
What the 1.6V minimum supply means for your design
The 1.6V floor is the key differentiator versus older 24Cxx parts that need 2.5V or 4.5V minimum. If your MCU runs on a 1.8V rail (common in battery-powered IoT or low-power sensor nodes), this EEPROM works directly without a boost converter. At the high end, the 5.5V absolute maximum (implied by the 1.6V to 5.5V operating range) lets it survive on a 5V rail with margin. The wide range also simplifies a dual-voltage design where the memory must follow the system into sleep mode at 1.8V and wake to 3.3V.