The AT29C040A is a 5-volt-only in-system Flash Programmable and Erasable Read Only Memory (PEROM). Its 4 megabits of memory is organized as 524,288 words by 8 bits. Manufactured with Atmel's advanced nonvolatile CMOS EEPROM technology, the device offers access times up to 100 ns, and a low 220 mW power dissipation. When the device is deselected, the CMOS standby current is less than 100 A. The device endurance is such that any sector can typically be written to in excess of 10,000 times. The programming algorithm is compatible with other devices in Atmel's 5-volt-only Flash family.