Product Descriptions

The Am27C256 is a 256-Kbit, ultraviolet erasable programmable read-only memory. It is organized as 32K words by 8 bits per word, operates from a single +5 V supply, has a static standby mode, and features fast single address location programming. Products are available in windowed ceramic DIP packages, as well as plastic one time programmable (OTP) PDIP and PLCC packages.

Data can be typically accessed in less than 55 ns, allowing high-performance microprocessors to operate without any WAIT states. The device offers separate Output Enable (OE#) and Chip Enable (CE#) controls, thus eliminating bus contention in a multiple bus microprocessor system.

AMD’s CMOS process technology provides high speed, low power, and high noise immunity. Typical power consumption is only 80 mW in active mode, and 100 µW in standby mode.

All signals are TTL levels, including programming signals. Bit locations may be programmed singly, in blocks, or at random. The device supports AMD’s Flashrite programming algorithm (100 µs pulses), resulting in a typical programming time of 4 seconds.

Product Features

■ Fast access time

— Speed options as fast as 45 ns

■ Low power consumption

— 20 µA typical CMOS standby current

■ JEDEC-approved pinout

■ Single +5 V power supply

■ ±10 percent power supply tolerance standard

■ 100 percent Flashrite™ programming

— Typical programming time of 4 seconds

■ Latch-up protected to 100 mA from –1 V to VCC + 1 V

■ High noise immunity

■ Versatile features for simple interfacing

— Both CMOS and TTL input/output compatibility

— Two line control functions

■ Standard 28-pin DIP, PDIP, and 32-pin PLCC packages

Product Photos

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