1GB-AUTO-AS4C128M8D3 Datasheet, PDF (44/84 Pages) Alliance Semiconductor Corporation – Fully synchronous operation

1Gb Auto-AS4C128M8D3
l Read Timing; Clock to Data Strobe relationship
Clock to Data Strobe relationship is shown in the following figure and is applied when the DLL is enabled and locked.
Rising data strobe edge parameters:
tDQSCK min/max describes the allowed range for a rising data strobe edge relative to CK and CK#. tDQSCK
is the actual position of a rising strobe edge relative to CK and CK#. tQSH describes the data strobe high pulse
width.
Falling data strobe edge parameters:
tQSL describes the data strobe low pulse width.
Figure 19. Clock to Data Strobe relationship
RL Measured
to this point
CLK#
CLK
DQS, DQS#
Early Strobe
DQS, DQS#
Late Strobe
t_{LZ(DQS) min}
t_{DQSCK (min)}
t_{DQSCK (min)}
t_{DQSCK (min)}
t_{DQSCK (min)}
t_QSH
t_QSL
t_QSH
t_QSL
t_QSH
t_QSL
t_{HZ(DQS) (min)}
t_RPRE
t_{LZ(DQS) max}
Bit 0
Bit 1
t_{DQSCK (max)}
Bit 2
Bit 3
t_{DQSCK (max)}
Bit 4
Bit 5
t_{DQSCK (max)}
t_RPST
Bit 6
Bit 7
t_{DQSCK (max)}
t_{HZ(DQS) (max)}
t_RPST
t_RPRE
t_QSH
t_QSL
t_QSH
t_QSL
t_QSH
t_QSL
Bit 0
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6
Bit 7
NOTES:
1. Within a burst, rising strobe edge is not necessarily fixed to be always at tDQSCK(min) or tDQSCK(max). Instead, rising strobe
edge can vary between tDQSCK(min) and tDQSCK(max).
2. Notwithstanding note 1, a rising strobe edge with tDQSCK(max) at T(n) can not be immediately followed by a rising strobe edge
with tDQSCK(min) at T(n+1). This is because other timing relationships (tQSH, tQSL) exist: if tDQSCK(n+1) < 0: tDQSCK(n) < 1.0 tCK -
(tQSHmin + tQSLmin) - | tDQSCK(n+1) |
3. The DQS, DQS# differential output high time is defined by tQSH and the DQS, DQS# differential output low time is defined by tQSL.
4. Likewise, tLZ(DQS)min and tHZ(DQS)min are not tied to tDQSCKmin (early strobe case) and tLZ(DQS)max and tHZ(DQS)max are
not tied to tDQSCKmax (late strobe case).
5. The minimum pulse width of read preamble is defined by tRPRE(min).
6. The maximum read postamble is bound by tDQSCK(min) plus tQSH(min) on the left side and tHZDSQ(max) on the right side.
7. The minimum pulse width of read postamble is defined by tRPST(min).
8. The maximum read preamble is bound by tLZDQS(min) on the left side and tDQSCK(max) on the right side.
Confidential
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Rev.1.0 May 2015