Am28F256A

The Am28F256A is a 256 K Flash memory organized as 32 Kbytes of 8 bits each. AMD's Flash memories offer the most cost-effective and reliable read/write non- volatile random access memory. The Am28F256A is packaged in 32-pin PDIP, PLCC, and TSOP versions It is designed to be reprogrammed and erased in-system or in standard EPROM programmers. The Am28F256A is erased when shipped from the factory.

The standard Am28F256A offers access times as fast as 70 ns, allowing operation of high-speed microprocessors without wait states. To eliminate bus contention, the Am28F256A has separate chip enable (CE#) and output enable (OE#) controls.AMD's Flash memories augment EPROM functionality with in-circuit electrical erasure and programming.

The Am28F256A uses a command register to manage this functionality, while maintaining a standard JEDEC Flash Standard 32-pin pinout. The command register allows for 100% TTL level control inputs and fixed
power supply levels during erase and programming.AMD's Flash technology reliably stores memory contents even after 100,000 erase and program cycles. The AMD cell is designed to optimize the erase and programming mechanisms. In addition, the combination of advanced tunnel oxide processing and low internal electric fields for erase and programming operations produces reliable cycling. The Am28F256A uses a 12.0V±5% VPP high voltage input to perform the erase and programming functions. The highest degree of latch-up protection is achieved with AMD's proprietary non-epi process. Latch-up protection is provided for stresses up to 100 milliamps on address and data pins from 1 V to VCC +1 V.

The Am28F256A is byte programmable using the Embedded Programming algorithm. The Embedded Programming algorithm does not require the system to
time-out or verify the data programmed. The typical room temperature programming time of the Am28F256A is one half second.

The entire chip is bulk erased using the Embedded Erase algorithm. The Embedded Erase algorithm automatically programs the entire array prior to electrical erase.