What is the diference between DDR-II SIO and QDR-II?

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Anonymous
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Dears:

   

I find that DDR-II SIO and QDR-II both have separate ports,but what is defference bwteen them?

   

Regards

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Anonymous
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          DDR-II Separate I/O products are a unique mix of QDR-II and DDR-II. They offer a separate input bus and a output port—like QDR-II—but only one port can be accessed  at any given time.    
   
         
   
    
      This resolves the bus contention of the common I/O DDR-II parts. It also avoids the QDR-II Burst of 2’s need for you to supply addresses at double data frequencies.     
   
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Anonymous
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 Hi NJY,

   

      What is mean  for "avoid the burst of 2's need" ? 

   

 

   

 

   

Thanks

   

Haiping

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Anonymous
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Haiping,

   

It means that for DDRII SIO devices, you do not need to supply addresses at double data rate unlike the QDRII Burst 2 device.

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Anonymous
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Hi, does that make it slower?  Or is it just as fast but I can use a slower address?  Thank you.

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Anonymous
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 This implies that the addresses dont need to be supplied at double data rate at the rising and falling edge of a clock.

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Anonymous
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Hi, so what are my max SI simulation speeds for DDR2 vs QDR2 SRAM?  Clocks, data, byte writes, address, and controls?  We can use 500MHz as an example clock speed (1000Mbps data rate).

   

Thanks again!

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Anonymous
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The max clock rate that we offer on the DDR2+ burst of 2 is 550MHz and QDR2+ burst of 2 is 333MHz.

   

The simulation speeds using an example of 300MHz are as follows.

   

For DDR2+ burst of 2 - clock, data, byte writes,  - 300MHz

   

                                          control, address - 150MHz

   


   

For QDR2+ burst of 2 - clock, data, byte writes, address - 300MHz

   

                                          control - 150MHz.

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