SN54ALS139 - Dual 2-Line To 4-Line Decoders/Demultiplexers

The ´ALS139 are dual 2-line to 4-line decoders/demultiplexers designed for use in high-performance memory-decoding or data-routing applications requiring very short propagation delay times. In high-performance memory systems, these devices can minimize the effects of system decoding. When employed with high-speed memories utilizing a fast-enable circuit, the delay times of these decoders and the enable time of the memory are usually less than the typical access time of the memory. Therefore, the effective system delay introduced by the Schottky-clamped system decoder is negligible.

The ´ALS139 comprise two individual 2-line to 4-line decoders in a single package. The active-low enable (G\) input can be used as a data line in demultiplexing applications. These decoders/demultiplexers feature fully buffered inputs, each of which represents only one normalized load to its driving circuit. All inputs are clamped with high-performance Schottky diodes to suppress line ringing and simplify system design.

The SN54ALS139 is characterized for operation over the full military temperature range of -55°C to 125°C. The SN74ALS139 is characterized for operation from 0°C to 70°C.

• Designed Specifically for High-Speed Memory Decoders and Data Transmission Systems
• Incorporate Two Enable Inputs to Simplify Cascading and/or Data Reception
• Package Options Include Plastic Small-Outline (D) Packages, Ceramic Chip Carriers (FK), and Standard Plastic (N) and Ceramic (J) 300-mil DIPs