Datasheet

Rev. 1.2 / Jul. 2013 24
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 below. 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
Vix Definition
Symbol Parameter
DDR3-800, 1066, 1333, 1600, 1866
Unit Notes
Min Max
V
IX
(CK)
Differential Input Cross Point Voltage
rela
tive to VDD/2 for CK,
CK
-150 150 mV 2
-175 175 mV 1
V
IX
(DQS)
Differential Input Cross Point Voltage
r
elative to VDD/2 for DQS,
DQS
-150 150 mV 2
No4tes:
1. Extended range for V
IX
is only allowed for clock and if single-ended clock input signals CK and CK are monotonic
with a single-ended swing VSEL / VSEH of at least VDD/2 +/-250 mV, and when the differential slew rate of CK -
CK is larger than 3 V/ns.
2. The relation between Vix Min/Max and VSEL/VSEH should satisf
y following.
(VDD/2) + Vix (Min) - VSEL  25
mV 
VSEH - ((VDD/2) + Vix (Max))  25mV
Cross point voltage for differential input signals (CK, DQS)