The 27C256 is a high-speed 256K UV erasable and electrically reprogrammable CMOS EPROM ideally suited for applications where fast turnaround pattern experimentation and low power consumption are important requirements The 27C256 is designed to operate with a single a 5V power supply with g 10% tolerance The CMOS design allows the part to operate over Military Temperature Range The 27C256 is packaged in a 28-pin dual-in-line package with transparent lid and a 32-pin windowed LCC The transparent lid allows the user to expose the chip to ultraviolet light to erase the bit pattern A new pattern can then be written electrically into the device by following the programming procedure This EPROM is fabricated with National's proprietary time proven CMOS double-poly silicon gate technology which combines high performance and high density with low power consumption and excellent reliability The 27C256 specified on this data sheet is fully compliant with MIL-STD-883 Revision C