General Description
The DS28E02 combines 1024 bits of EEPROM with challenge-and-response authentication security implemented with the FIPS 180-3 Secure Hash Algorithm (SHA-1). The 1024-bit EEPROM array is configured as four pages of 256 bits with a 64-bit scratchpad to perform write operations. All memory pages can be write protected, and one page can be put in EPROM-emulation mode, where bits can only be changed from a 1 to a 0 state. Each DS28E02 has its own guaranteed unique 64-bit ROM registration number that is factory installed into the chip. The DS28E02 communicates over the single-contact 1-Wire® bus. The communication follows the standard 1-Wire protocol with the registration number acting as the node address in the case of a multidevice 1-Wire network.

FEATUREs
♦ 1024 Bits of EEPROM Memory Partitioned Into Four Pages of 256 Bits
♦ On-Chip 512-Bit SHA-1 Engine to Compute 160- Bit Message Authentication Codes (MACs) and to Generate Secrets
♦ Write Access Requires Knowledge of the Secret and the Capability of Computing and Transmitting a 160-Bit MAC as Authorization
♦ User-Programmable Page Write Protection for Page 0, Page 3, or All Four Pages Together
♦ User-Programmable OTP EPROM Emulation Mode for Page 1 (“Write to 0”)
♦ Communicates to Host with a Single Digital Signal at 12.5kbps or 35.7kbps Using 1-Wire Protocol
♦ Switchpoint Hysteresis and Filtering to Optimize Communication Performance in the Presence of Noise
♦ Reads and Writes Over 1.75V to 3.65V Voltage Range from -20°C to +85°C
♦ 6-Lead TSOC and TDFN Packages