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DDR_x4x8x16_Core2.fm - 256Mb DDR: Rev. O, Core DDR: Rev. B 1/09 EN
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2003 Micron Technology, Inc. All rights reserved.
256Mb: x4, x8, x16 DDR SDRAM
Operations
Figure 35:
x4, x8 Data Output Timing – tDQSQ, tQH, and Data Valid Window
Notes:
1. tHP is the lesser of tCL or tCH clock transition collectively when a bank is active.
2. tDQSQ is derived at each DQS clock edge, is not cumulative over time, begins with DQS
transition, and ends with the last valid DQ transition.
3. DQ transitioning after DQS transition define the tDQSQ window. DQS transitions at T2 and
T2n are an “early DQS”; at T3, a “nominal DQS”; and at T3n, a “l(fā)ate DQS”.
4. For a x4, only two DQ apply.
5. tQH is derived from tHP: tQH = tHP - tQHS.
6. The data valid window is derived for each DQS transitions and is defined as tQH - tDQSQ.
DQ (last data valid)
DQ4
DQS
3
DQ (last data valid)
DQ (first data no longer valid)
All DQ and DQS collectively
6
Earliest signal transition
Latest signal transition
T2
T2n
T3
T3n
CK
CK#
T1
T2
T3
T4
T2n
T3n
tQH5
tHP1
tQH5
tHP1
tQH5
tDQSQ2
Data
valid
window
Data
valid
window
Data
valid
window
Data
valid
window