W631GG6KB-15 Datasheet, PDF (87/158 Pages) Winbond – Double Data Rate architecture: two data transfers per clock cycle

W631GG6KB
7.19.4 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): tAONPD,min,max, tAOFPD,min,max.
Minimum RTT turn-on time (tAONPDmin) is the point in time when the device termination circuit leaves high impedance state and ODT resistance begins to
turn on. Maximum RTT turn on time (tAONPDmax) is the point in time when the ODT resistance is fully on.
tAONPDmin and tAONPDmax are measured from ODT being sampled high.
Minimum RTT turn-off time (tAOFPDmin) is the point in time when the devices termination circuit starts to turn off the ODT resistance. Maximum ODT turn
off time (tAOFPDmax) is the point in time when the on-die termination has reached high impedance. tAOFPDmin and tAOFPDmax are measured from ODT
being sampled low.
T0
T1
T2
T3
T4
T5
T6
T7
T8
T9
T10
T11
T12
T13
T14
T15
T16
T17
CK#
CK
CKE
tIH
tIS
tIH tIS
ODT
RTT
tAONPDmin
tAONPDmax
RTT
tAOFPDmin
tAOFPDmax
TRANSITIONING
DON'T CARE
Figure 82 – Asynchronous ODT Timings on DDR3 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
tAONPD Asynchronous RTT turn-on delay (Power-Down with DLL frozen)
2
8.5
nS
tAOFPD Asynchronous RTT turn-off delay (Power-Down with DLL frozen)
2
8.5
nS
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Publication Release Date: Feb. 27, 2013
Revision A04