MT40A1G8WE-075E Datasheet, PDF (279/358 Pages) Micron Technology – Refresh time of 8192-cycle at TC temperature range

8Gb: x8, x16 Automotive DDR4 SDRAM
Electrical Characteristics – AC and DC Differential Input Meas-
urement Levels
DQS Differential Input Cross Point Voltage
To achieve tight RxMask input requirements as well as output skew parameters with re-
spect to strobe, the cross point voltage of differential input signals (DQS_t, DQS_c) must
meet V_{IX_DQS,ratio} in the table below. The differential input cross point voltage V _{IX_DQS}
(V_{IX_DQS_FR} and V_{IX_DQS_RF}) is measured from the actual cross point of DQS_t, DQS_c
relative to the V_DQS,mid of the DQS_t and DQS_c signals.
V_DQS,mid is the midpoint of the minimum levels achieved by the transitioning DQS_t
and DQS_c signals, and noted by V_{DQS_trans}. V_{DQS_trans} is the difference between the low-
est horizontal tangent above V_DQS,mid of the transitioning DQS signals and the highest
horizontal tangent below V_DQS,mid of the transitioning DQS signals. A non-monotonic
transitioning signal’s ledge is exempt or not used in determination of a horizontal tan-
gent provided the said ledge occurs within ±35% of the midpoint of either V_IH.DIFF.Peak
voltage (DQS_t rising) or V_IL.DIFF.Peak voltage (DQS_c rising), as shown in the figure be-
low.
A secondary horizontal tangent resulting from a ring-back transition is also exempt in
determination of a horizontal tangent. That is, a falling transition’s horizontal tangent is
derived from its negative slope to zero slope transition (point A in the figure below), and
a ring-back’s horizontal tangent is derived from its positive slope to zero slope transi-
tion (point B in the figure below) and is not a valid horizontal tangent; a rising transi-
tion’s horizontal tangent is derived from its positive slope to zero slope transition (point
C in the figure below), and a ring-back’s horizontal tangent derived from its negative
slope to zero slope transition (point D in the figure below) and is not a valid horizontal
tangent.
Figure 220: V_IXDQS Definition
DQS_t
Lowest horizontal tanget above V_DQS,mid
of the transitioning signals
C
V_DQS,mid
V_{IX_DQS,FR}
V_{IX_DQS,RF}
V_{IX_DQS,FR}
B
D
V_{IX_DQS,RF}
DQS_c
A
V_SSQ
Highest horizontal tanget below V_DQS,mid
of the transitioning signals
Table 106: Cross Point Voltage For Differential Input Signals DQS
Parameter
DQS_t and DQS_c crossing relative to the
midpoint of the DQS_t and DQS_c signal
swings
Symbol
V_{IX_DQS,ratio}
DDR4-1600, 1866, 2133, 2400,
2666, 2933, 3200
Min
Max
–
25
Unit
%
Notes
1, 2
CCMTD-1406124318-10419
8gb_auto_ddr4_dram.pdf - Rev. C 3/17 EN
279
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