NTC Proprietary
Level: Property
DDR3(L)-2Gb SDRAM
NT5CB(C)256M8JQ/NT5CB(C)128M16JR
Auto Self-Refresh mode - ASR mode
DDR3(L) SDRAM provides an Auto-Refresh mode (ASR) for application ease. ASR mode is enabled by setting MR2 bit
A6=1 and MR2 bit A7=0. The DRAM will manage Self-Refresh entry in either the Normal or Extended Temperature Ranges.
In this mode, the DRAM will also manage Self-Refresh power consumption when the DRAM operating temperature changes,
lower at low temperatures and higher at high temperatures. If the ASR option is not supported by DRAM, MR2 bit A6 must
set to 0. If the ASR option is not enabled (MR2 bit A6=0), the SRT bit (MR2 bit A7) must be manually programmed with the
operating temperature range required during Self-Refresh operation. Support of the ASR option does not automatically imply
support of the Extended Temperature Range.
Self-Refresh Temperature Range - SRT
SRT applies to devices supporting Extended Temperature Range only. If ASR=0, the Self-Refresh Temperature (SRT)
Range bit must be programmed to guarantee proper self-refresh operation. If SRT=0, then the DRAM will set an appropriate
refresh rate for Self-Refresh operation in the Normal Temperature Range. If SRT=1, then the DRAM will set an appropriate,
potentially different, refresh rate to allow Self-Refresh operation in either the Normal or Extended Temperature Ranges. The
value of the SRT bit can effect self-refresh power consumption, please refer to IDD table for details.
Self-Refresh mode summary
Allowed Operating
MR2
A[6]
MR2
A[7]
Self-Refresh operation
Temperature Range for
Self-Refresh mode
Normal 1
0
0
0
1
Self-Refresh rate appropriate for the Normal Temperature Range
Self-Refresh appropriate for either the Normal or Extended Temperature Ranges.
The DRAM must support Extended Temperature Range. The value of the SRT bit
can effect self-refresh power consumption, please refer to the IDD table for details.
Normal and Extended 2
ASR enabled (for devices supporting ASR and Normal Temperature Range). Self-
Refresh power consumption is temperature dependent.
Normal 1
1
1
0
ASR enabled (for devices supporting ASR and Extended Temperature Range). Self-
Refresh power consumption is temperature dependent.
Normal and Extended 2
0
1
1
Illegal
NOTES:
1. The Normal range depends on product’s grade.
- Automotive Grade 2 (-H) = -40℃~85℃
- Automotive Grade 3 (-A) = -40℃~85℃
2. The Normal and Extended range depends on product’s grade.
- Automotive Grade 2 (-H) = -40℃~105℃
- Automotive Grade 3 (-A) = -40℃~95℃
Version 1.4
05/2019
43
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