描述 Description

The AT49BV/LV040 are 3-volt-only, 4-megabit Flash memories organized as 524,288 words of 8-bits each. Manufactured with Atmel’s advanced nonvolatile CMOS tech nology, the devices offer access times to 120 ns with power dissipation of just 90 mW over the commercial temperature range. When the device is deselected, the CMOS standby current is less than 50 μA.
The device contains a user-enabled “boot block” protection feature. Two versions of the feature are available: the AT49BV/LV040 locates the boot block at lowest order addresses (“bottom boot”); the AT49BV/LV040T locates it at highest order addresses (“top boot”).
To allow for simple in-system reprogrammability, the AT49BV/LV040 does not require high input voltages for programming. Three-volt-only commands determine the read and programming operation of the device. Reading data out of the device is similar to reading from an EPROM. Reprogramming the AT49BV/LV040 is performed by erasing the entire 4 megabits of memory and then programming on a byte-by-byte basis. The typical byte programming time is a fast 30 μs. The end of a program cycle can be optionally detected by the DATA polling feature. Once the end of a byte program cycle has been detected, a new access for a read or program can begin. The typical number of program and erase cycles is in excess of 10,000 cycles.
The optional 16K bytes boot block section includes a reprogramming write lock out feature to provide data integrity. The boot sector is designed to contain user secure code, and when the feature is enabled, the boot sector is permanently protected from being reprogrammed.

特性 Features

? Single Voltage for Read and Write: 2.7V to 3.6V (BV), 3.0V to 3.6V (LV)
? Fast Read Access Time - 120 ns
? Internal Program Control and Timer
? 16K bytes Boot Block With Lockout
? Fast Chip Erase Cycle Time - 10 seconds
? Byte-by-Byte Programming - 30 μs/Byte Typical
? Hardware Data Protection
? DATA Polling For End Of Program Detection
? Low Power Dissipation
?? – 25 mA Active Current
?? – 50 μA CMOS Standby Current
? Typical 10,000 Write Cycles
? Small Packaging
?? – 8 x 8 mm CBGA
?? – 8 x 14 mm V-TSOP