64 Kbit serial EEPROM for multi-voltage I²C buses
The Microchip 24CW640T-I/MUY is a 64 Kbit serial EEPROM organized as 8K x 8 bits, accessed over an I²C interface running at up to 1 MHz. The 450 ns access time is the read-cycle latency from the last address clock-in to the first data bit out — tight enough for most MCU polling loops, but budget a wait state if the host I²C peripheral expects immediate data. Write-cycle time per page is 5 ms, typical for this density class.
Microchip lists the 24CW640T-I/MUY as an Active product. The series is 24CW, and the suffix -I/MUY indicates the industrial temperature grade and the 8-UDFN package variant. ROHS3 compliance is confirmed.
Package and footprint — 8-UDFN with exposed pad
For the PCB layout, the pad should be connected to ground (or left floating if the datasheet recommends it) and stitched with vias to the inner ground plane for heat dissipation during page-write cycles. The part is surface-mount only. No special bake is required beyond standard MSL handling — verify the MSL level on the reel label before reflow.