Article ID: 000079193 Content Type: Troubleshooting Last Reviewed: 09/11/2012

Does ALTMEMPHY based DDR3 SDRAM controller IP support automatic slew rate deration for a DDR3 SDRAM device with speed grade greater than or equal to 667MHz at AC175 specification?

Environment

  • Quartus® II Subscription Edition
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    Critical Issue

    Description

    No, ALTMEMPHY based DDR3 SDRAM controller only supports memory timing specification less than or equal to 533MHz at AC175 specification.

    If you need to use faster device than 533Mhz, you have to manually derate using AC150 specification and enter the values directly to the MegaWizard™ GUI by using below calculation:

    tDS (VREF) = Base tDS delta tDS (VIH(AC) – VREF)/slew_rate
    tDH (VREF) = Base tDH delta tDH (VIH(DC) – VREF)/slew_rate

    Related Products

    This article applies to 3 products

    Stratix® IV GX FPGA
    Stratix® III FPGAs
    Stratix® IV E FPGA

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