XDR DRAM

From Freepedia

XDR DRAM is a high performance RAM Interface like SDR-SDRAM and DDR-SDRAM. The XDR solution was engineered to be effective in small high-bandwidth consumer systems as well as in high-performance main memory applications. Rambus owns the technology. XDR is the official choice by Sony for the Playstation 3 console.

Parameters

Performance:

• clock rate at 400 MHz (600, 800 and 1000 MHz planned)
• 8 bits per clock and lane (ODR = Octal Data Rate) gives 3.2 GBit/s (4.8, 6.4 and 8 Gbit/s planned)
• 8 or 16 lanes per chip gives 3.2 to 16 GByte/s

Features:

• Bi-directional differential RSL (DRSL)
• Programmable on-chip termination
• Adaptive impedance matching
• 8 bank memory architecture
• Up to 4 Bank-interleaved transactions at full bandwidth
• Point-to-point data interconnect
• CSP packaging
• Dynamic request scheduling
• Early-read-after-write support for maximum efficiency
• Zero overhead refresh

Low power:

• 1.8V Vdd
• Programmable ultra-low-voltage DRSL 200mV swing
• Low-power PLL/DLL design
• Power-down self-refresh support
• Dynamic data width support with dynamic clock gating
• Per pin I/O power-down
• Sub-page activation support

Ease in system design:

• Per bit FlexPhase circuits compensate to a 2.5 ps resolution
• XDR Interconnect uses minimum pin count

Low latency

• 1.25/2.0/2.5/3.33 ns request packets

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• Successor XDR-II DRAM is planned to start in 2007: "XDR2 to quintuple memory data transfer speeds by 2007" by Scott Fulton

(is DRSL the same as LVDS ?) [1], [2], [3].