6402 datasheet(49/250 Pages) INTEL

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Intel® 6400/6402 Advanced Memory Buffer Datasheet

Electrical, Power, and Thermal

4.4.9

Write Preamble Duration

The write preamble duration is the measurement from the point when DQS and DQS

start to be driven, to the crossing point of DQS and DQS. Typically, to determine when

DQS and DQS are starting to be driven, timing measurements are made at 0.5xVCC +/

- 50 mV, and 0.5xVCC +/- 100 mV, and then the measurements are linearly

extrapolated back to 0.5xVCC.

4.4.10

Write Postamble Duration

The write postamble duration is the measurement from the crossing point of DQS and

DQS, to the point where DQS and DQS start to go into a high impedance state.

Typically, to determine when DQS and DQS are starting to go into a high impedance

state, for DQS, timing measurements are made at Vlow + 50 mV, and Vlow + 100 mV,

and then the measurements are linearly extrapolated back to Vlow. For DQS, timing

measurements are made at Vhigh - 50 mV, and Vhigh - 100 mV, and then the

measurements are extrapolated back to Vhigh.

Figure 4-8. Write Preamble Duration Timing Diagram

tWPREamb

DQS

(AMB)

0.5xVCC

Figure 4-9. Write Postamble Duration Timing Diagram

DQS

(A M B )

0.5x V C C

t W P S T a m b

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