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Table 31: DDR2-667/800/1066 tDS, tDH Derating Values with Differential Strobe
All units are shown in picoseconds
DQ
Slew
Rate
(V/ns)
DQS, DQS# Differential Slew Rate
2.8 V/ns
2.4 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
0.8 V/ns
Δ
tDS
Δ
tDH
Δ
tDS
Δ
tDH
Δ
tDS
Δ
tDH
Δ
tDS
Δ
tDH
Δ
tDS
Δ
tDH
Δ
tDS
Δ
tDH
Δ
tDS
Δ
tDH
Δ
tDS
Δ
tDH
Δ
tDS
Δ
tDH
2.0
100
63
100
63
100
63
112
75
124
87
136
99
148
111
160
123
172
135
1.5
67
42
67
42
67
42
79
54
91
66
103
78
115
90
127
102
139
114
1.0
0
12
24
36
48
60
72
0.9
–5
–14
–5
–14
–5
–14
7
–2
19
10
31
22
43
34
55
46
67
58
0.8
–13
–31
–13
–31
–13
–31
–1
–19
11
–7
23
5
35
17
47
29
59
41
0.7
–22
–54
–22
–54
–22
–54
–10
–42
2
–30
14
–18
26
–6
38
6
50
18
0.6
–34
–83
–34
–83
–34
–83
–22
–71
–10
–59
2
–47
14
–35
26
–23
38
–11
0.5
–60 –125 –60 –125 –60 –125 –48 –113 –36 –101 –24
–89
–12
–77
0
–65
12
–53
0.4
–100 –188 –100 –188 –100 –188 –88 –176 –76 –164 –64 –152 –52 –140 –40 –128 –28 –116
Notes: 1. For all input signals the total tDS and tDH required is calculated by adding the data
sheet value to the derating value listed in
Table 31.2. tDS 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. tDS nominal slew rate for a falling
signal is defined as the slew rate between the last crossing of VREF(DC) and the first cross-
ing of VIL(AC)max. If the actual signal is always earlier than the nominal slew rate line
between the shaded “VREF(DC) to AC region,” use the nominal slew rate for the derating
line anywhere between shaded “VREF(DC) to AC region,” the slew rate of a tangent line
to the actual signal from the AC level to DC level is used for the derating value (see
Fig-3. tDH 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). tDH nominal slew rate for a falling
signal is defined as the slew rate between the last crossing of VIH(DC)min and the first cross-
ing of VREF(DC). If the actual signal is always later than the nominal slew rate line
between the shaded “DC level to VREF(DC) region,” use the nominal slew rate for the de-
slew rate line anywhere between the 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 the derat-
4. Although the total setup time might be negative for slow slew rates (a valid input signal
will not have reached VIH[AC]/VIL[AC] at the time of the rising clock transition), a valid in-
put signal is still required to complete the transition and reach VIH(AC)/VIL(AC).
5. For slew rates between the values listed in this table, the derating values may be ob-
tained by linear interpolation.
6. These values are typically not subject to production test. They are verified by design and
characterization.
DQS single-ended slew rate derating with DQS referenced at VREF and DQ referenced at
the logic levels tDSb and tDHb. Converting the derated base values from DQ referenced
ble 33 provides the VREF-based fully derated values for the DQ (tDSa and tDHa) for 1Gb: x4, x8, x16 1.55V DDR2 SDRAM
Input Slew Rate Derating
PDF: 09005aef82b91d01
1GbDDR2_1_55V.PDF Rev. A 5/09 EN
58
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