W632GU6NB
Publication Release Date: Aug. 20, 2018
Revision: A01
- 89 -
8.19.4 Asynchronous ODT Mode
Asynchronous ODT mode is selected when DRAM runs in DLLon mode, but DLL is temporarily disabled (i.e. frozen) in precharge power-down (by MR0 bit
A12). Based on the power down mode definitions, this is currently Precharge power down mode if DLL is disabled during precharge power down by MR0
bit A12.
In asynchronous ODT timing mode, internal ODT command is NOT delayed by Additive Latency (AL) relative to the external ODT command.
In asynchronous ODT mode, the following timing parameters apply (see Figure 82): t
AONPD,
min
,
max, t
AOFPD,
min
,
max.
Minimum R
TT
turn-on time (t
AONPD
min) is the point in time when the device termination circuit leaves high impedance state and ODT resistance begins to
turn on. Maximum R
TT
turn on time (t
AONPD
max) is the point in time when the ODT resistance is fully on.
t
AONPD
min and t
AONPD
max are measured from ODT being sampled high.
Minimum R
TT
turn-off time (t
AOFPD
min) is the point in time when the devices termination circuit starts to turn off the ODT resistance. Maximum ODT turn
off time (t
AOFPD
max) is the point in time when the on-die termination has reached high impedance. t
AOFPD
min and t
AOFPD
max are measured from ODT
being sampled low.
T0
T1
T2
T4
CK#
CK
T5
T3
ODT
T6
T7
T8
T9
T10
T12
T13
T14
T15
T11
T16
T17
t
AONPDmin
t
IH
RTT
t
IS
t
AONPDmax
RTT
t
AOFPDmin
t
AOFPDmax
t
IH
t
IS
CKE
TRANSITIONING
DON'T CARE
Figure 82
– Asynchronous ODT Timings on DDR3L SDRAM with fast ODT transition: AL is ignored
In Precharge Power Down, ODT receiver remains active, however no Read or Write command can be issued, as the respective ADD/CMD receivers may
be disabled.
Table 12
– Asynchronous ODT Timing Parameters for all Speed Bins
Symbol
Description
Min.
Max.
Unit
t
AONPD
Asynchronous R
TT
turn-on delay (Power-Down with DLL frozen)
2
8.5
nS
t
AOFPD
Asynchronous R
TT
turn-off delay (Power-Down with DLL frozen)
2
8.5
nS