Datasheet

Command and Address Setup, Hold, and Derating
The total
t
IS (setup time) and
t
IH (hold time) required is calculated by adding the data
sheet
t
IS (base) and
t
IH (base) values (see Table 57; values come from the Electrical
Characteristics and AC Operating Conditions table) to the Δ
t
IS and Δ
t
IH derating values
(see Table 58 (page 94), Table 59 (page 94) or Table 60 (page 94)) respectively. Ex-
ample:
t
IS (total setup time) =
t
IS (base) + Δ
t
IS. For a valid transition, the input signal
has to remain above/below V
IH(AC)
/V
IL(AC)
for some time
t
VAC (see Table 61 (page 95)).
Although the total setup time for slow slew rates might be negative (for example, a valid
input signal will not have reached V
IH(AC)
/V
IL(AC)
at the time of the rising clock transi-
tion), a valid input signal is still required to complete the transition and to reach
V
IH(AC)
/V
IL(AC)
(see Figure 11 (page 43) for input signal requirements). For slew rates that
fall between the values listed in Table 58 (page 94) and Table 60 (page 94), the derat-
ing values may be obtained by linear interpolation.
Setup (
t
IS) nominal slew rate for a rising signal is defined as the slew rate between the
last crossing of V
REF(DC)
and the first crossing of V
IH(AC)min
. Setup (
t
IS) nominal slew rate
for a falling signal is defined as the slew rate between the last crossing of V
REF(DC)
and
the first crossing of V
IL(AC)max
. If the actual signal is always earlier than the nominal slew
rate line between the shaded V
REF(DC)
-to-AC region, use the nominal slew rate for derat-
ing value (see Figure 30 (page 96)). If the actual signal is later than the nominal slew
rate line anywhere between the shaded V
REF(DC)
-to-AC region, the slew rate of a tangent
line to the actual signal from the AC level to the DC level is used for derating value (see
Figure 32 (page 98)).
Hold (
t
IH) nominal slew rate for a rising signal is defined as the slew rate between the
last crossing of V
IL(DC)max
and the first crossing of V
REF(DC)
. Hold (
t
IH) nominal slew rate
for a falling signal is defined as the slew rate between the last crossing of V
IH(DC)min
and
the first crossing of V
REF(DC)
. If the actual signal is always later than the nominal slew
rate line between the shaded DC-to-V
REF(DC)
region, use the nominal slew rate for derat-
ing value (see Figure 31 (page 97)). If the actual signal is earlier than the nominal slew
rate line anywhere between the shaded DC-to-V
REF(DC)
region, the slew rate of a tangent
line to the actual signal from the DC level to the V
REF(DC)
level is used for derating value
(see Figure 33 (page 99)).
Table 57: DDR3L Command and Address Setup and Hold Values 1 V/ns Referenced – AC/DC-Based
Symbol 800 1066 1333 1600 1866 2133 Unit Reference
t
IS(base, AC160) 215 140 80 60 – – ps V
IH(AC)
/V
IL(AC)
t
IS(base, AC135) 365 290 205 185 65 60 ps V
IH(AC)
/V
IL(AC)
t
IS(base, AC125) ––––150135psV
IH(AC)
/V
IL(AC)
t
IH(base, DC90) 285 210 150 130 110 105 ps V
IH(DC)
/V
IL(DC)
8Gb: x4, x8, x16 DDR3L SDRAM
Command and Address Setup, Hold, and Derating
93
Rev 2.0 June 2016
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