SDRAM Question

Hi all,

I am trying to understand how SDRAM works, but some things I don't understand:

1) Do I have to refresh while I am in burst cycle (say I am in full BANK write mode), if so what happens after refresh is finished, do I have to activate row again, or can I just keep writing.

2) What is the actual data rate (typical) for a 133MHz SDRAM?

3) does auto refresh follow PRECHARGE command?

4) Finally- why is SRAM considered faster thqan SDRAM, I checked an SRAMs by Toshiba, and as far as I understood, it's data rate was 16MHz, so this doesn't seem so fast to me, what am I not understanding here?

Getting the spec sheet for any SDRAM will answer your questions 1 - 3. The data rate on that SRAM sounds awfully slow.

udylevy,

What part number? 16mhz is too slow maybe 160mhz.

SRAM part number is TC55257 by Toshiba. The Data Setup time is 60nS, so doesn't this prevent working frequency to >=16MHz?

j.p.bill said:

Getting the spec sheet for any SDRAM will answer your questions 1 - 3. The data rate on that SRAM sounds awfully slow.

Click to expand...

I did look at the spec, but I am not sure I understood it right. My main question is what is the actual data rate of the SDRAM, since it's not specified directly in the datasheet, I need to understand how it works to calculate it.