Hi CKW,
I don't know that you want the capacitance to be specified, as this would
greatly limit design options. I don't think the resistance is specified either.
The scope section of JEDEC Standard 8-9 (SSTL 2.5V) says:
"Actual selection of the resistor values is a system design decision and
beyond the scope of this standard."
This might be similar with the 1.8V version?
I recommend you select these values based on what gives the best signaling
and timing margins in the design.
best regards,
Stephanie
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Please respond to
ckw1972
Hi,
I've a question on the DDR-II SDRAM (SSTL-18 class-II) spec as below,
can someone help me to understand this correctly? Thanks in advance.
1. Why they is no clear capacitance load spec specify on the memory
spec?
For example, samsung 512M 200Mhz DDR-II SSTL-18 class-II device
datasheet
only specify their AC load reference is just connect DQ pin to
Vtt thru one 25ohm
resistor. My understanding on this is with Cload=5pF & Cload=0pF
will impact on
the 200Mhz performance quite significantly.
Thanks
Regards,
CKW
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