GENERAL DESCRIPTION

The AS27C256 series is a set of 262,144 bit, ultraviolet-light erasable, electrically programmable read-only memories. These devices are fabricated using power-saving CMOS technology for high speed and simple interface with MOS and bipolar circuits. All inputs (including program data inputs) can be

driven by Series 54 TTL circuits without the use of external pullup resistors. Each output can drive one Series 54 TTL circuit without external resistors. The data outputs are 3-state for connecting multiple devices to a common bus. The AS27C256 is pin-compatible with 28-pin 256K ROMs and

EPROMs. It is offered in a 600mil dual-in-line ceramic package (J suffix) and a 450 x 550 mil ceramic LCC (ECA suffix) rated for operation from -55°C to 125°C.

FEATURES

? Organized 32,768 x 8

? Single +5V ±10 power supply

? Pin-compatible with existing 256K ROM’s and EPROM’s

? All inputs/outputs fully TTL compatible

? Power-saving CMOS technology

? Very high-speed FLASHRITE Pulse Programming

? 3-state output buffers

? 400-mV DC assured noise immunity with standard TTL loads

? Latchup immunity of 250 mA on all input and output pins

? Low power dissipation (CMOS Input Levels)

-Active - 165mW Worst Case

-Standby - 1.7mW Worst Case (CMOS-input levels)

* FUTURE High Speed Offerings: 55ns, 70ns, 90ns