AS4C256M16D3
READ Timing Definitions
Read timing 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, CK#. tDQSCK is the
actual position of a rising strobe edge relative to CK, CK#. tQSH describes the DQS, DQS# differential output
high time. tDQSQ describes the latest valid transition of the associated DQ pins. tQH describes the earliest
invalid transition of the associated DQ pins.
Falling data strobe edge parameters:
tQSL describes the DQS, DQS# differential output low time. tDQSQ describes the latest valid transition of the
associated DQ pins. tQH describes the earliest invalid transition of the associated DQ pins.
tDQSQ; both rising/falling edges of DQS, no tAC defined.
Figure 18. READ timing Definition
CK#
CK
tDQSCK,min
tDQSCK,min
tDQSCK,max
tDQSCK,max
Rising Strobe
Region
Rising Strobe
Region
tDQSCK
tDQSCK
tQSL
tQSH
DQS#
DQS
tQH
tQH
tDQSQ
tDQSQ
Associated
DQ Pins
Confidential
42
Rev. 3.0
Aug. /2014
ALSC [ ALLIANCE SEMICONDUCTOR CORPORATION ]
