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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