Datasheet

Timing Parameter
In synchronous ODT mode, the following parameters apply:
 DODTLon, DODTLoff, RODTLoff, RODTLon4, RODTLon8, t
ADC (MIN) (MAX)
.
 t
ADC (MIN)
and t
ADC (MAX)
are minimum and maximum R
TT
change timing skew between different termination
values. These timing parameters apply to both the synchronous ODT mode and the data termination disable
mode.
When ODT is asserted, it must remain high until minimum ODTH4 (BL = 4) or ODTH8 (BL = 8) is satisfied.
Additionally, depending on CRC or 2t
CK
preamble setting in MRS, ODTH should be adjusted.
T0 T1 T2 T3 T4 T5 T6 T7 T8 T9
T10 T11
CK#
CK
T12 T13 T14
TRANSITIONING DATA
T15 T16 T17
RTT
t
ADC
(min)
CMD
ODT
DODTLon = WL - 2
DODTLoff = WL - 2
R
TT_PARK
t
ADC
(max)
R
TT_NOM
t
ADC
(min)
t
ADC
(max)
R
TT_PARK
diff
Figure 164. Synchronous ODT Timing Example for CWL=9, AL=0, PL=0; DODTLon=WL-2=7;
DODTLoff=WL-2=7
T0 T1 T2 T5 T18 T19 T20 T21 T22 T23
T36 T37
CK#
CK
T38 T39 T40
TRANSITIONING DATA
T41 T42 T43
RTT
t
ADC
(min)
CMD
ODT
ODTH4
DODTLoff = WL - 2
R
TT_PARK
t
ADC
(max)
R
TT_NOM
t
ADC
(min)
t
ADC
(max)
R
TT_PARK
t
ADC
(min)
t
ADC
(max)
t
ADC
(min)
t
ADC
(max)
R
TT_PARK
R
TT_WR
DODTLon = WL - 2
WRS4
ODTLcnw = WL - 2
ODTLcnw4 = ODTcnw+4
diff
Figure 165. Synchronous ODT example with BL=4, CWL=9, AL=10, PL=0; DODTLon/off=WL-2=17,
ODTcnw=WL-2=17
ODT must be held high for at least ODTH4 after assertion (T1). ODTHis measured from ODT first registered
high to ODT first registered low, or from registration of Write command. Note that ODTH4 should be adjusted
depending on CRC or 2t
CK
preamble setting.
AS4C256M16D4
Confidential
- 150 of 201 -
Rev.1.0 Aug.2019