Description
The AT28HC256 is a high-performance electrically erasable and programmable read-only memory. Its 256K of memory is organized as 32,768 words by 8 bits. Manufactured with Atmel’s advanced nonvolatile CMOS technology, the AT28HC256 offers access times to 70 ns with power dissipation of just 440 mW. When the AT28HC256 is deselected, the standby current is less than 5 mA.

FEATUREs
• Fast Read Access Time – 70 ns
• Automatic Page Write Operation
   – Internal Address and Data Latches for 64 Bytes
   – Internal Control Timer
• Fast Write Cycle Times
   – Page Write Cycle Time: 3 ms or 10 ms Maximum
   – 1 to 64-byte Page Write Operation
• Low Power Dissipation
   – 80 mA Active Current
   – 3 mA Standby Current
• Hardware and Software Data Protection
• DATA Polling for End of Write Detection
• High Reliability CMOS Technology
   – Endurance: 104 or 105 Cycles
   – Data Retention: 10 Years
• Single 5V ±10% Supply
• CMOS and TTL Compatible Inputs and Outputs
• JEDEC Approved Byte-wide Pinout
• Full Military and Industrial Temperature Ranges
• Green (Pb/Halide-free) Packaging Option