描述 Description

The Direct Rambus DRAM (Direct RDRAM) is a general purpose high-performance memory device suitable for use in a broad range of applications including computer memory, graphics, video, and any other application where high bandwidth and low latency are required.

The μPD488588 is 288Mbits Direct Rambus DRAM (RDRAM?), organized as 16M words by 18 bits. The use of Rambus Signaling Level (RSL) technology permits 600MHz to 800MHz transfer rates while using conventional system and board design technologies. Direct RDRAM devices are capable of sustained data transfers at 1.25ns per two bytes (10ns per sixteen bytes).

The architecture of the Direct RDRAMs allows the highest sustained bandwidth for multiple, simultaneous randomly addressed memory transactions. The separate control and data buses with independent row and column control yield over 95 bus efficiency. The Direct RDRAM’s four banks support up to four simultaneous transactions.

System oriented features for mobile, graphics and large memory systems include power management, byte masking.

The μPD488588 is offered in a CSP horizontal package suitable for desktop as well as low-profile add-in card and mobile applications. Direct RDRAMs operate from a 2.5V supply.

特性 Features

? Highest sustained bandwidth per DRAM device

— 1.6 GB/s sustained data transfer rate

— Separate control and data buses for maximized

efficiency

— Separate row and column control buses for easy

scheduling and highest performance

— 32 banks: four transactions can take place

simultaneously at full bandwidth data rates

? Low latency features

— Write buffer to reduce read latency

— 3 precharge mechanisms for controller flexibility

— Interleaved transactions

? Advanced power management:

— Multiple low power states allows flexibility in power

consumption versus time to active state

— Power-down self-refresh

? Overdrive current mode

? Organization: 2K bytes pages and 32 banks, x 18

? Uses Rambus Signaling Level (RSL) for up to 800MHz operation

? Package : 80-ball FBGA (μ?BGA?) (17.16 × 10.2)