1 / 15

High-Speed DRAMs: A Roadmap

This article provides an introduction to high-speed DRAMs, including fast DRAMs using multi-banks, graphics DRAMs, and pseudo-SRAMs. It discusses the different types of DRAMs and their applications, as well as the evolution of high-speed DRAM interfaces. The article emphasizes the need for reducing latency and increasing speed in memory systems.

jbeverly
Download Presentation

High-Speed DRAMs: A Roadmap

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. App. Specific DRAMs Eyad Al-Hazmi

  2. Roadmap • Introduction • High-Speed DRAMs • Fast DRAMs using Multi Banks • Graphics DRAMs • Pseudo-SRAMs

  3. Introduction • DRAM, Dynamic Random Access Memory • Historically been high volume, standard memory • Many DRAM applications differing in requirements • Many types of DRAMs

  4. High-Speed DRAMs • DRAMs were asynchronous with processor .... • Sometimes processor access while refreshing • Processor has to wait for interrupt req. from memory TOTAL WASTE OF TIME !!! • Examples: FPM DRAM

  5. High-Speed DRAMs Cont. • A synchronous interface was added to DRAM • DRAM is under system clock control • Permits adding control features behind it • Made a huge improvement in speed • Examples: SDRAM (speed = 133 MHz, Operating voltage = 3.3 V)

  6. High-Speed DRAMs Cont.

  7. High-Speed DRAMs Cont. • A DDR interface was added to DRAM • Allowing of fetching two words per one cycle • Data rate = 2*Clock frequency • Examples: DDR SDRAM, DDRII SDRAM

  8. High-Speed DRAMs Cont.

  9. Fast DRAMs using Multi-Banks • Reduces the capacitance of word lines • Two Designs; Different characteristics • Goal: Reduction of Read Latency

  10. CS CS R/W R/W R/W CS Address Address . . . Address Data Data m m Data . . Data width = m × p bits Fast DRAMs using Multi-Banks Cont.

  11. CS CS R/W R/W R/W Address Address Data Data m m m m Fast DRAMs using Multi-Banks Cont. n+k k k to 2k decoder Address n . . . CS . . . Address Data Data width = m bits

  12. Graphics DRAM (VRAM) • Requirements: • Lower memory system density • Higher speed than main memory applications • Wide I/O bus to match system bus • Need for few DRAMs  DRAMs can be closer • Uses point-to-point interface to increase I/O speed

  13. Pseudo-SRAM (PSRAM) • DRAM inside – SRAM outside (SRAM Interface) • DRAMs with SRAM interfaces first appeared in 1980s • High density and power requirements, motivation to • make newer SRAM interface DRAMs, beginning of • PSRAMs.

  14. Summery • Introduction • High-Speed DRAMs • Fast DRAMs using Multi Banks • Graphics DRAMs • Pseudo-SRAMs

  15. Thank You...

More Related