Vix(ac), ac differential input cross point voltage, Figure 24: vref table (table 23 from jesd79-3e) – Teledyne LeCroy QPHY-DDR3 User Manual

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917717 Rev C

VIX(ac), AC Differential Input Cross Point Voltage

The typical value of VIX(ac) is expected to be about 0.5 x VDDQ of the transmitting device and VIX(ac) is
expected to track variations in VDDQ. VIX(ac) indicates the voltage at which differential input signals must
cross.

Vref(DC)

It is the linear average of Vref (t) over a very long period of time (e.g., 1 sec). This average has to meet
the min/max requirements in Table below. Furthermore V(t) may temporarily deviate from Vref(DC) by no
more than +/- 1% VDD.

Figure 22: Vref table (Table 23 from JESD79-3E)

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