2Gb DDR3L – AS4C128M16D3L
- Address / Command Setup, Hold and Derating
For all input signals the total tIS (setup time) and tIH (hold time) required is calculated by adding the data sheet
tIS(base) and tIH(base) and tIH(base) value to the delta tIS and delta tIH derating value respectively.
Example: tIS (total setup time) = tIS(base) + delta tIS.
Setup (tIS) nominal slew rate for a rising signal is defined as the slew rate between the last crossing of Vref(dc) and
the first crossing of VIH(ac)min. Setup (tIS) nominal slew rate for a falling signal is defined as the slew rate between
the last crossing of Vref(dc) and the first crossing of VIL(ac)max. If the actual signal is always earlier than the
nominal slew rate line between shaded ‘Vref(dc) to ac region’, use nominal slew rate for derating value. If the actual
signal is later than the nominal slew rate line anywhere between shaded ‘Vref(dc) to ac region’, the slew rate of the
tangent line to the actual signal from the ac level to dc level is used for derating value.
Hold (tIH) nominal slew rate for a rising signal is defined as the slew rate between the last crossing of VIL(dc)max
and the first crossing of Vref(dc). Hold (tIH) nominal slew rate for a falling signal is defined as the slew rate between
the last crossing of VIH(dc)min and the first crossing of Vref(dc). If the actual signal is always later than the nominal
slew rate line between shaded ‘dc to Vref(dc) region’, use nominal slew rate for derating value. If the actual signal is
earlier than the nominal slew rate line anywhere between shaded ‘dc to Vref(dc) region’, the slew rate of a tangent
line to the actual signal from the dc level to Vref(dc) level is used for derating value. For a valid transition the input
signal has to remain above/below VIH/IL(ac) for some time tVAC. Although for slow slew rates the total setup time
might be negative (i.e. a valid input signal will not have reached VIH/IL(ac) at the time of the rising clock transition) a
valid input signal is still required to complete the transition and reach VIH/IL(ac).
Table 40. ADD/CMD Setup and Hold Base - Values for 1V/ns
Symbol
Reference
VIH/L(ac)
VIH/L(ac)
VIH/L(dc)
-12
60
Unit
ps
tIS(base) AC160
tIS(base) AC135
tIH(base) DC90
185
ps
130
ps
NOTE 1: (ac/dc referenced for 1V/ns Address/Command slew rate and 2 V/ns differential CK-CK# slew rate)
NOTE 2: The tIS(base) AC135 specifications are adjusted from the tIS(base) specification by adding an additional 100ps of
derating to accommodate for the lower alternate threshold of 135mV and another 25 ps to account for the earlier reference point
[(160 mv - 135 mV) / 1 V/ns].
Table 41. Derating values DDR3L-1600 tIS/tIH – (AC160)
△t , △t derating in [ps] AC/DC based Alternate AC160 Threshold -> VIH(ac)=VREF(dc)+160mV, VIL(ac)=VREF(dc)-160mV
IS
IH
CK, CK# Differential Slew Rate
4.0 V/ns
3.0 V/ns
2.0 V/ns
1.8 V/ns 1.6 V/ns
1.4 V/ns
1.2 V/ns
1.0 V/ns
△tIS
△tIH
45
30
0
△tIS
△tIH
45
30
0
△tIS
△tIH
45
30
0
△tIS
△tIH
53
38
8
△tIS
△tIH
61
46
16
13
9
△tIS
△tIH
69
54
24
21
17
11
4
△tIS
△tIH
79
64
34
31
27
21
14
4
△tIS
△tIH
95
80
50
47
43
37
30
20
5
CMD
/ADD
Slew
Rate
V/ns
2.0
1.5
1.0
0.9
0.8
0.7
0.6
0.5
0.4
80
53
0
80
53
0
80
53
0
88
61
8
96
69
16
15
13
11
8
104
77
24
23
21
19
16
4
112
85
32
31
29
27
24
12
-8
120
93
40
39
37
35
32
20
0
-1
-3
-1
-3
-1
-3
7
5
-3
-8
-3
-8
-3
-8
5
1
-5
-13
-20
-30
-45
-5
-13
-20
-30
-45
-5
-13
-20
-30
-45
3
-5
3
-8
-8
-8
0
-12
-22
-37
-4
-20
-40
-20
-40
-20
-40
-12
-32
-4
-14
-29
-6
-24
-16
-21
-11
Confidential
58
Rev. 2.0
Aug. /2014
ALSC [ ALLIANCE SEMICONDUCTOR CORPORATION ]
