W949D6DB Datasheet, PDF (29/60 Pages) Winbond – Standard Self Refresh Mode

W949D6DB / W949D2DB
8.5.2 Basic Read Timing Parameters
t_CK
t_CK
CK
CK
DQS
t_ACmax
t_CH
t_CL
t_DQSCK
t_RPRE
t_DQSCK
t_RPST
t_DQSQmax
t_AC
t_HZ
DQ
DO n DO n+1 DO n+2 DO n+3
t_LZ
t_QH
t_QH
DQS
t_ACmin
DQ
t_DQSCK
t_RPRE
t_DQSCK
t_RPST
t_AC
t_LZ
t_DQSQmax
t_HZ
DO n
t_QH
DO n+1 DO n+2 DO n+3
t_QH
1) DO n = Data Out from column n
2) All DQ are valid tAC after the CK edge.
All DQ are valid tDQSQ after the DQS edge, regardless of tAC
= Don't Care
During Read bursts, DQS is driven by the LPDDR SDRAM along with the output data. The initial Low
state of the DQS is known as the read preamble; the Low state coincident with last data-out element is
known as the read postamble. The first data-out element is edge aligned with the first rising edge of
DQS and the successive data-out elements are edge aligned to successive edges of DQS. This is shown
in following figure with a CAS latency of 2 and 3.
Upon completion of a read burst, assuming no other READ command has been initiated, the DQs will
go to High-Z.
- 29 -
Publication Release Date: Oct. 08, 2014
Revision: A01-003