AS4C64M32MD2-25BCN datasheet(85/129 Pages) ALSC

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7.5 Differential Input Cross Point Voltage

To guarantee tight setup and hold times as well as output skew parameters with respect to clock and strobe, each

cross point voltage of differential input signals (CK, CK# and DQS, DQS#) must meet the requirements in Table 28.

The differential input cross point voltage VIX is measured from the actual cross point of true and complement signals

to the midlevel between of VDD and VSS.

Figure 7.6 — Vix Definition

Table 29 — Cross point voltage for differential input signals (CK, DQS)

Symbol

Parameter

LPDDR2-800

Unit

Notes

Min

Max

VIXCA

Differential Input Cross Point Voltage

relative to VDDCA/2 for CK, CK#

-120

120

1,2

VIXDQ

Differential Input Cross Point Voltage

relative to VDDQ/2 for DQS, DQS#

-120

120

1,2

NOTE 1 The typical value of VIX(AC) is expected to be about 0.5 × VDD of the transmitting device, and VIX(AC) is expected to track

variations in VDD. VIX(AC) indicates the voltage at which differential input signals must cross.

NOTE 2 For CK and CK#, Vref = VrefCA(DC). For DQS and DQS#, Vref = VrefDQ(DC).

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AS4C64M32MD2-25BCN Datasheet(PDF) 85 Page - Alliance Semiconductor Corporation