AS4LC4M16S0

The AS4LC8M8S0 and AS4LC4M16S0 are high-performance 64-megabit CMOS Synchronous Dynamic Random Access Memory (SDRAM) devices organized as 2,097,152 words × 8 bits × 4 banks, and 1,048,576 words × 16 bits × 4 banks, respectively. Very high bandwidth is achieved using a pipelined architecture where all inputs and outputs are referenced to the rising edge of a common clock. Programmable burst mode can be used to read up to a full page of data without selecting a new column address.

The four internal banks of AS4LC4M16S0 can be alternately accessed (read or write) at the maximum clock frequency for seamless interleaving operations. This provides a significant advantage over asynchronous EDO and fast page mode devices.

This SDRAM product also features a programmable mode register, allowing users to select read latency as well as burst length and type (sequential or interleaved). Lower latency improves first data access in terms of CLK cycles, while higher latency improves maximum frequency of operation. This feature of AS4LC4M16S0 enables flexible performance optimization for a variety of applications.

DRAM commands and functions of AS4LC4M16S0 are decoded from control inputs. Basic commands are as follows:
• Mode register set                       • Deactivate bank              • Deactivate all banks                • Select row; activate bank
• Select column; write                   • Select column; read         • Deselect; power down            • CBR refresh
• Auto precharge with read/write • Self-refresh

The 64 Mb DRAM devices are available in 400-mil plastic TSOP II packages and have 54 pins in each configuration. Both devices operate with a power supply of 3.3V ± 0.3V. Multiple power and ground pins are provided for low switching noise and EMI. Inputs and outputs are LVTTL-compatible.