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Visitor
Visitor
5,500 Views
Registered: ‎09-16-2009

ZRQ value on SP605 vs UG388

Hi, Two things- UG388 has RZQ value as 240 ohms but SP605 has a 100 ohm resistor for RZQ. I will copy the SP605 schematic but would like to know why there is a discrepancy. Second, you might include a note in UG388 with giant arrows and stars about terminating the A, BA, RAS, CAS, WE lines like the SP605, and note about the VTTREF signals on B1,M8, P8, K8 . Some idiot might lay out a PCB without them if they just read UG388.
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Voyager
Voyager
5,459 Views
Registered: ‎05-21-2008

240 ohm is for RZQ of DDR3 component. 100ohm RZQ is for Spartan RZQ pin. They are different. Please check DDR3 spec for more infor for 240ohm RZQ.
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