W632GU6NB
Publication Release Date: Aug. 20, 2018
Revision: A01
- 94 -
8.19.4.4 Asynchronous to Synchronous ODT Mode during short CKE high and short CKE low periods
If the total time in Precharge Power Down state or Idle state is very short, the transition periods for PD entry and PD exit may overlap (see Figure 86). In
this case, the response of the DDR3L SDRAMs R
TT
to a change in ODT state at the input may be synchronous OR asynchronous from the start of the PD
entry transition period to the end of the PD exit transition period (even if the entry period ends later than the exit period).
If the total time in Idle state is very short, the transition periods for PD exit and PD entry may overlap. In this case the response of the DDR3L SDRAMs
R
TT
to a change in ODT state at the input may be synchronous OR asynchronous from the start of the PD exit transition period to the end of the PD entry
transition period. Note that in the bottom part of Figure 86 it is assumed that there was no Refresh command in progress when Idle state was entered.
T0
T1
T2
T4
CK#
CK
T5
T3
Command
T6
T7
T8
T9
T10
T12
T13
T14
T11
CKE
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
NOP
REF
CKE
t
RFC
(min)
t
ANPD
PD entry transition period
PD exit transition period
t
ANPD
short CKE low transition period
t
ANPD
short CKE high transition period
t
XPDLL
TIME BREAK
TRANSITIONING
DON'T CARE
t
XPDLL
Figure 86
– Transition period for short CKE cycles, entry and exit period overlapping (AL = 0, WL = 5, t
ANPD
= WL - 1 = 4)