Why we cannot use one 2Gibt DDR2 ram instead of two 1Gbit DDR2 RAMs

[mitr]

Hi,

I have a doubt regarding the ddr 2 meomroy. I have processor to DDR2 interfaces where I am interfacing 2 nos of 1Gibt DDR 2 RAMs. Each Ram is 16 bit data wide. I am using 32 bit data from processor to two ddr 2 RAMs.

Instead I can use a Single 2 Gbit DDR2 ram which is of 16 bit wide? In that case the data will not be accessed faster than two 1 Gbit DDR2 as the in the 1Gibt DDR2 case 32 bit of DDR2 DATA interface is used to fetch the data from the 1Gibt ddr2 memory. But for one number of 2Gibt DDR2 ram only 16 bit data access only results in fecting data at 1Gbit ram speed only(due to only 16 bit data interface). Only difference is there are 2 bit memory locations.

Is my understanding right?

Will there be any DDR2 memory ICs with 32 bit data interface to the processor?

Regards
KIL

 

[sivamani]

I don't think so 32 bit ddrs available...if your requirement is to have 32 bit data(for faster access) and memory is not a constraint then u need to use two ddr chips..

 

[mitr]

I don't think so 32 bit ddrs available...if your requirement is to have 32 bit data(for faster access) and memory is not a constraint then u need to use two ddr chips..

Hi,

I have just googled a Winbond ddr2 sdram has the 32 bit data interface. I am not sure it is a standard data bit interface. I have seen 8 bit,16 bit but not 32 bit in DDR2. Below is the link for the datasheet.

**broken link removed**

My query is if we have 32 bit data 2Gbit ddr-2 sdram and two nos of 1Gigabit DDR-2 sdram of 16 bit data interface, which of the two will have faster data access from the ddr-2 to the processor?

 

[sivamani]

You can use this..but i don't know weather multiple vendor support is there or not..if the part is gets obsolete

 

[mitr]

You can use this..but i don't know weather multiple vendor support is there or not..if the part is gets obsolete

My query is if we have 32 bit data 2Gbit ddr-2 sdram and two nos of 1Gigabit DDR-2 sdram of 16 bit data interface, which of the two will have faster data access from the ddr-2 to the processor?

 

[sivamani]

Accessing from DDR is depends on DDR timing spec not on Data width.