MT40A1G8WE-083E Datasheet, PDF (143/358 Pages) Micron Technology – Automotive DDR4 SDRAM

8Gb: x8, x16 Automotive DDR4 SDRAM
Fine Granularity Refresh Mode
• In the fixed 2x refresh rate mode or the enable-OTF 1x/2x refresh rate mode, it is rec-
ommended there be an even number of REF2x commands before entry into self re-
fresh after the last self refresh exit, REF1x command, or MRS command that set the
refresh mode. If this condition is met, no additional REFRESH commands are re-
quired upon self refresh exit. In the case that this condition is not met, either one ex-
tra REF1x command or two extra REF2x commands must be issued upon self refresh
exit. These extra REFRESH commands are not counted toward the computation of the
average refresh interval (^tREFI).
• In the fixed 4x refresh rate mode or the enable-OTF 1x/4x refresh rate mode, it is rec-
ommended there be a multiple-of-four number of REF4x commands before entry in-
to self refresh after the last self refresh exit, REF1x command, or MRS command that
set the refresh mode. If this condition is met, no additional refresh commands are re-
quired upon self refresh exit. When this condition is not met, either one extra REF1x
command or four extra REF4x commands must be issued upon self refresh exit. These
extra REFRESH commands are not counted toward the computation of the average
refresh interval (^tREFI).
There are no special restrictions on the fixed 1x refresh rate mode.
This section does not change the requirement regarding postponed REFRESH com-
mands. The requirement for the additional REFRESH command(s) described above is
independent of the requirement for the postponed REFRESH commands.
CCMTD-1406124318-10419
8gb_auto_ddr4_dram.pdf - Rev. C 3/17 EN
143
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