GENERAL DESCRIPTION

The MT28F004B3 (x8) and MT28F400B3 (x16/x8) are nonvolatile, electrically block-erasable (flash), programmable memory devices containing 4,194,304 bits organized as 262,144 words (16 bits) or 524,288 bytes (8 bits). Writing or erasing the device is done with either a 3.3V or 5V VPP voltage, while all operations are performed with a 3.3V VCC. Due to process technology advances, 5V VPP is optimal for application and production programming. These devices are fabricated with Micron’s advanced 0.18μm CMOS floating-gate process.

The MT28F004B3 and MT28F400B3 are organized into seven separately erasable blocks. To ensure that critical firmware is protected from accidental erasure or overwrite, the devices feature a hardware-protected boot block. Writing or erasing the boot block requires either applying a super-voltage to the RP# pin or driving WP# HIGH in addition to executing the normal write or erase sequences. This block may be used to store code implemented in low-level system recovery. The remaining blocks vary in density and are written and erased with no additional security measures.

FEATURES

? Seven erase blocks:

16KB/8K-word boot block (protected)

Two 8KB/4K-word parameter blocks

Four main memory blocks

? Smart 3 technology (B3):

3.3V ±0.3V VCC

3.3V ±0.3V VPP application programming

5V ±10 VPP application/production programming1

? Compatible with 0.3μm Smart 3 device

? Advanced 0.18μm CMOS floating-gate process

? Address access time: 80ns

? 100,000 ERASE cycles

? Industry-standard pinouts

? Inputs and outputs are fully TTL-compatible

? Automated write and erase algorithm

? Two-cycle WRITE/ERASE sequence

? Byte- or word-wide READ and WRITE

(MT28F400B3, 256K x 16/512K x 8)

? Byte-wide READ and WRITE only

(MT28F004B3, 512K x 8)

? TSOP and SOP packaging options