Type: Answers

Type: Errata

Area: EMIF

Area: Intellectual Property


IP Product: DDR3 SDRAM Controller supporting ALTMEMPHY

Why devices faster than 533MHz require manual derating?

Description

In the DDR3 SDRAM Controllers with ALTMEMPHY IP MegaCore® functions version 10.1 and earlier,  the controller provides automatic derating based on the AC175 threshold. Memory devices faster than 533 MHz require derating based on the AC150 threshold.

Affected Configurations

This issue affects all configurations using memory devices faster than 533 MHz.

Design Impact

This issue can result in inaccurate timing analysis.

Solution Status

This issue is fixed in the DDR3 SDRAM Controllers with ALTMEMPHY IP MegaCore function version 11.0 .

Workaround/Fix

To workaround this issue, you need to calculate derated setup and hold values for your memory device, and enter those values in the DDR3 SDRAM Controller with ALTMEMPHY parameter editor.