The Microchip AT24CSW040 is a 4 Kb Serial EEPROM utilizing an I²C (2-wire) serial interface. The device is organized as one block of 512 x 8 and is optimized for use in consumer applications where reliable and dependable nonvolatile memory storage is essential. The device features Software Write Protection, which can be used to write protect 1/4, 1/2, or the entire memory array and also provides the user the capability to make the write protection permanent. Additionally, the AT24CSW040 includes a 256-bit security register separate from the main array. The first half of the security register contains a 128-bit factory-programmed unique serial number while the remaining half is a user programmable and permanently lockable space. The 128-bit serial number is guaranteed unique across the entire CS series of Serial EEPROM products and eliminates the time consuming step of performing and ensuring serialization of a product on a manufacturing line.

• 512 x 8 (4 Kbit)
• 400 kHz and 1 MHz clock compatibility
• Factory set hardware slave address
• Software Write Protection with five configuration options
• Protection settings can be made permanent
• Factory programmed 128-bit unique serial number
• Self-Timed Erase and Write Cycles (5 ms max.)
• Read current 0.15 mA (Typ), 0.5 mA (Max)
• Write current 0.2 mA (Typ), 1 mA (Max)
• Standby current 0.1 uA (Typ), 0.8 uA (Max)
• More than 1 million erase/write cycles
• Data retention > 100 years
• Available in a 4-ball Ultra-thin WLCSP package