ED14R126-12AMBTEL datasheet(21/51 Pages) EOREX

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Single-ended requirements for differential signals

Each individual component of a differential signal (CK, DQS, DQSL, DQSU, CK, DQS, DQSL, of DQSU) has

also to comply with certain requirements for single-ended signals.

CK and CK have to approximately reach VSEHmin / VSELmax (approximately equal to the ac-levels (VIH

(ac) / VIL (ac)) for ADD/CMD signals) in every half-cycle.

DQS, DQSL, DQSU, DQS, DQSL have to reach VSEHmin / VSELmax (approximately the ac-levels (VIH (ac)

/ VIL (ac)) for DQ signals) in every half-cycle preceding and following a valid transition.

Note that the applicable ac-levels for ADD/CMD and DQ’s might be different per speed-bin etc. E.g., if

VIH.CA(AC150)/VIL.CA(AC150) is used for ADD/CMD signals, then these ac-levels apply also for the single-

ended signals CK and CK.

VDD or VDDQ

VSEHmin

VSEH

VDD/2 or VDDQ/2

VSELmax

CK or DQS

VSS or VSSQ

VSEL

time

Single-ended requirements for differential signals.

Note that, while ADD/CMD and DQ signal requirements are with respect to Vref, the single-ended compo-

nents of differential signals have a requirement with respect to VDD / 2; this is nominally the same. the

transition of single-ended signals through the ac-levels is used to measure setup time. For single-ended

components of differential signals the requirement to reach VSELmax, VSEHmin has no bearing on timing,

but adds a restriction on the common mode characteristics of these signals.

ED14R126-12AMBTEL Datasheet(PDF) 21 Page - Eorex Corporation