2. M95640-RDW6TP Substitution Conclusion Direct substitution is feasible based on parametric specifications, but application validation is required. This part (manufactured by ST) is compatible with the original part in core specifications: 64-Kbit density (8K x 8), a wide 1.8V to 5.5V supply voltage range, a 5ms write cycle time, and an identical 8-TSSOP package. The most significant technical difference is its maximum SPI clock frequency of 20 MHz, which is twenty times that of the original part, enabling very high-speed data read operations. However, the manufacturer difference necessitates verification of full compatibility within the specific application. This includes checking SPI timing with the host microcontroller, the instruction set (e.g., Write Enable, Status Register commands), power-on sequencing, and internal page size (while the organization is identical, the byte boundaries for page write operations may differ slightly). It can be considered a high-performance alternative, but functional and reliability testing on the target hardware and software is recommended prior to final substitution.