Datasheet
Read Timing; Data Strobe to Data relationship
The Data Strobe to Data relationship is shown below and is applied when the DLL is enabled and locked.
Rising data strobe edge parameters:
t
DQSQ
describes the latest valid transition of the associated DQ pins.
t
QH
describes the earliest invalid transition of the associated DQ pins.
Falling data strobe edge parameters:
t
DQSQ
describes the latest valid transition of the associated DQ pins.
t
QH
describes the earliest invalid transition of the associated DQ pins.
t
DQSQ
; both rising/falling edges of DQS, no tAC defined.
Data Valid Window:
t
DVWd
is the Data Valid Window per device per UI and is derived from (t
QH
- t
DQSQ
) of each UI on a given
DRAM. This parameter will be characterized and guaranteed by design.
t
DVWp
is Data Valid Window per pin per UI and is derived from (t
QH
- t
DQSQ
) of each UI on a pin of a given
DRAM. This parameter will be characterized and guaranteed by design.
T1 Ta0 Ta1 Ta2 Ta3 Ta4 Ta5 Ta6T0
RL = AL +CL +PL
DESREAD DES DES DES DES DES DES DES
Bank,
Col n
t
DQSQ (max)
Dout
n+1
Dout
n+2
Dout
n+3
Dout
n+4
Dout
n+5
Dout
n+6
Dout
n+1
Dout
n+2
Dout
n+3
Dout
n+4
Dout
n+5
Dout
n+6
CK#
ADDR
CK
CMD
DQS,DQS#
DQ
(Last data valid)
All DQs collectively
DQ
(First data no longer valid)
t
RPRE
t
QH
t
QH
t
DQSQ (max)
t
RPST
NOTE 1. BL = 8, AL = 0, CL = 11, Preamble = 1
tCK
NOTE 2. Dout n = data-out from column n.
NOTE 3. DES commands are shown for ease of illustration; other commands may be valid at these times.
NOTE 4. BL8 setting activated by either MR0[A1:0 = 00] or MR0[A1:0 = 01] and A12 = 1 during READ command at T0.
NOTE 5. Output timings are referenced to VDDQ, and DLL on for locking.
NOTE 6. t
DQSQ
defines the skew between DQS,DQS# to Data and does not define DQS, DQS# to Clock.
NOTE 7. Early Data transitions may not always happen at the same DQ. Data transitions of a DQ can vary (either early or late) within a burst.
DON'T CARETRANSITIONING DATA
Dout
n
Dout
n+7
Dout
n
Dout
n+7
t
DVWP
Dout n
Dout
n+1
Dout
n+2
Dout
n+3
Dout
n+4
Dout
n+5
Dout
n+6
Dout
n+7
Figure 88. Data Strobe to Data Relationship
AS4C256M16D4
Confidential
- 92 of 201 -
Rev.1.0 Aug.2019