DESCRIPTION
The DS1609 is a random access 256–byte dual port memory designed to connect two asyncronous address/data buses together with a common memory element. Both ports have unrestricted access to all 256 bytes of memory, and with modest system discipline no arbitration is required. Each port is controlled by three control signals: output enable, write enable, and port enable. The device is packaged in plastic 24–pin DIP and 24–pin SOIC. Output enable access time of 50 ns is available when operating at 5 volts.

FEATURES
• Totally asynchronous 256–byte dual port memory
• Multiplexed address and data bus keeps pin count low
• Dual port memory cell allows random access with minimum arbitration
• Each port has standard independent RAM control signals
• Fast access time
• Low power CMOS design
• 24–pin DIP or 24–pin SOIC surface mount package
• Both CMOS and TTL compatible
• Operating temperature of –40°C to +85°C
• Standby current of 100 nA @ 25°C makes the device ideal for battery backup or battery operate applications.