Description
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 90 ns, and a low 220 mW power dissipation. When the device is deselected, the CMOS standby current is less than 100 µA. 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.
To allow for simple in-system reprogrammability, the AT29C040A does not require high input voltages for programming. Five-volt-only commands determine the operation of the device. Reading data out of the device is similar to reading from an EPROM. Reprogramming the AT29C040A is performed on a sector basis; 256 bytes of data are loaded into the device and then simultaneously programmed.

Features
• Fast Read Access Time – 90 ns
• 5-volt Only Reprogramming
• Sector Program Operation
   – Single Cycle Reprogram (Erase and Program)
   – 2048 Sectors (256 Bytes/Sector)
   – Internal Address and Data Latches for 256 Bytes
• Internal Program Control and Timer
• Hardware and Software Data Protection
• Two 16K Bytes Boot Blocks with Lockout
• Fast Sector Program Cycle Time – 10 ms
• DATA Polling for End of Program Detection
• Low Power Dissipation
   – 40 mA Active Current
   – 100 µA CMOS Standby Current
• Typical Endurance > 10,000 Cycles
• Single 5V ± 10% Supply
• CMOS and TTL Compatible Inputs and Outputs