DDR3 AC or DC Logic Levels

[ankit.ahlawat]

Hi Sir,
I am want to start advance hardware design so that am start reading Datasheet of DDR3 Memory and Processor. Here i found different voltage level (AC and DC). I already know about DC logic level but i don't know about AC logic level? When am going to search on internet i found nothing. They showing me only voltage range but i want to know what is mean of AC Logic Levels. Sir Please help, am stuck here.

[robertferanec]

Please, can you attached specific datasheet?

[chitransh92]

Hello,
The AC values corresponds to the acceptable noise levels on the signal.
This is related to the speed grade of the DDR3 memory.

For AC175 for speed grades 400.0 (DDR3-800) & 533.333 (DDR3-1066).
Means for this grade the allowed noise levels are Vref + 175mV

For AC150 it is Vref+150mV and so on.

If the noise levels are more than the AC voltage limit for that particular interface than DDR3 Interface is not considered to be JEDEC compliant and is prone to failures and mall-operation.

Thank you.