EDJ1108BABG, EDJ1116BABG
DLL Enable (MR1)
The DLL must be enabled for normal operation. DLL enable is required during power-up initialization, and upon
returning to normal operation after having the DLL disabled. The DLL is automatically disabled when entering self-
refresh operation and is automatically re-enabled upon exit of self-refresh operation. Any time the DLL is enabled
and subsequently reset, tDLLK clock cycles must occur before a read or synchronous ODT command can be issued
to allow time for the internal clock to be synchronized with the external clock. Failing to wait for synchronization to
occur may result in a violation of the tDQSCK, tAON or tAOF parameters. During tDLLK, CKE must continuously be
registered high.
DDR3 SDRAM does not require DLL for any write operation. DDR3 does not require DLL to be locked prior to any
write operation. DDR3 requires DLL to be locked only for read operation and to achieve synchronous ODT timing.
DLL-off Mode
DDR3 DLL-off mode is entered by setting MR1 bit A0 to 1; this will disable the DLL for subsequent operations until
A0 bit set back to 0. The MR1 A0 bit for DLL control can be switched either during initialization or later.
The DLL-off mode operations listed below are an optional feature for DDR3. The maximum clock frequency for DLL-
off mode is specified by the parameter tCKDLL_OFF. There is no minimum frequency limit besides the need to
satisfy the refresh interval, tREFI.
Due to latency counter and timing restrictions, only one value of /CAS Latency (CL) in MR0 and CAS Write Latency
(CWL) in MR2 are supported. The DLL-off mode is only required to support setting of both CL = 6 and CWL = 6.
DLL-off mode will affect the Read data Clock to Data Strobe relationship (tDQSCK) but not the Data Strobe to Data
relationship (tDQSQ, tQH, tQHS). Special attention is needed to line up Read data to controller time domain.
Comparing with DLL-on mode, where tDQSCK starts from the rising clock edge (AL + CL) cycles after the Read
command, the DLL-off mode tDQSCK starts (AL + CL − 1) cycles after the read command. Another difference is that
tDQSCK may not be small compared to tCK (it might even be larger than tCK) and the difference between tDQSCK
(min.). and tDQSCK (max.) is significantly larger than in DLL-on mode.
The timing relations on DLL-off mode READ operation are shown at following Timing Diagram (CL = 6, BL8):
T0
T1
T2
T3
T4
T5
T6
T7
T8
T9
CK, /CK
Command
READ
A
BA
DQSdiff_DLL-on
RL = AL + CL = 6 (CL = 6, AL = 0)
CL = 6
DQ_DLL-on
CA0 CA1 CA2 CA3 CA4 CA5 CA6 CA7
RL (DLL-off) = AL + (CL - 1) = 5
tDQSCK(DLL-off)_min
DQSdiff_DLL-off
DQ_DLL-off
CA0 CA1 CA2 CA3 CA4 CA5 CA6 CA7
tDQSCK(DLL-off)_max
DQSdiff_DLL-off
DQ_DLL-off
CA0 CA1 CA2 CA3 CA4 CA5 CA6 CA7
DLL-Off Mode Read Timing Operation
Data Sheet E1248E40 (Ver. 4.0)
80
ELPIDA [ ELPIDA MEMORY ]
