Datasheet

Figure 77: Method for Calculating
t
LZ and
t
HZ
t
HZDQS,
t
HZDQ
t
HZDQS,
t
HZDQ end point = 2 × T1 - T2
V
OH
- xmV
V
TT
- xmV
V
OL
+ xmV
V
TT
+ xmV
V
OH
- 2xmV
V
TT
- 2xmV
V
OL
+ 2xmV
V
TT
+ 2xmV
t
LZDQS,
t
LZDQ
t
LZDQS,
t
LZDQ begin point = 2 × T1 - T2
T1
T1
T2
T2
Notes:
1. Within a burst, the rising strobe edge is not necessarily fixed at
t
DQSCK (MIN) or
t
DQSCK
(MAX). Instead, the rising strobe edge can vary between
t
DQSCK (MIN) and
t
DQSCK
(MAX).
2. The DQS HIGH pulse width is defined by
t
QSH, and the DQS LOW pulse width is defined
by
t
QSL. Likewise,
t
LZDQS (MIN) and
t
HZDQS (MIN) are not tied to
t
DQSCK (MIN) (early
strobe case), and
t
LZDQS (MAX) and
t
HZDQS (MAX) are not tied to
t
DQSCK (MAX) (late
strobe case); however, they tend to track one another.
3. The minimum pulse width of the READ preamble is defined by
t
RPRE (MIN). The mini-
mum pulse width of the READ postamble is defined by
t
RPST (MIN).
Figure 78:
t
RPRE Timing
t
RPRE
DQS - DQS#
DQS
DQS#
T1
t
RPRE begins
T2
t
RPRE ends
CK
CK#
V
TT
Resulting differential
signal relevant for
t
RPRE specification
t
C
t
A
t
B
t
D
Single-ended signal provided
as background information
0V
Single-ended signal provided
as background information
V
TT
V
TT
8Gb: x4, x8, x16 DDR3L SDRAM
READ Operation
162
Rev 2.0 June 2016
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