AS4C256M16D3
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.
Table 22. Self-Refresh mode summary
Allowed Operating
Temperature Range
for Self-Refresh mode
MR2 MR2
A[6] A[7]
Self-Refresh operation
Self-Refresh rate appropriate for the Normal Temperature Range
0
0
0
1
Normal (0 ~ 85C)
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
(0 ~ 95C)
ASR enabled (for devices supporting ASR and Normal Temperature
Range).Self-Refresh power consumption is temperature dependent.
1
1
1
0
0
1
Normal (0 ~ 85C)
Normal and Extended
(0 ~ 95C)
ASR enabled (for devices supporting ASR and Extended Temperature
Range).Self-Refresh power consumption is temperature dependent.
Illegal
ACTIVE Command
The ACTIVE command is used to open (or activate) a row in a particular bank for subsequent access. The value
on the BA0-BA2 inputs selects the bank, and the addresses provided on inputs A0-A14 selects the row. These
rows remain active (or open) for accesses until a precharge command is issued to that bank. A PRECHARGE
command must be issued before opening a different row in the same bank.
PRECHARGE Command
The PRECHARGE command is used to deactivate the open row in a particular bank or the open row in all banks.
The bank(s) will be available for a subsequent row activation a specified time (tRP) after the PRECHARGE
command is issued, except in the case of concurrent auto precharge, where a READ or WRITE command to a
different bank is allowed as long as it does not interrupt the data transfer in the current bank and does not violate
any other timing parameters. Once a bank has been precharged, it is in the idle state and must be activated prior
to any READ or WRITE commands being issued to that bank. A PRECHARGE command is allowed if there is no
open row in that bank (idle bank) or if the previously open row is already in the process of precharging. However,
the precharge period will be determined by the last PRECHARGE command issued to the bank.
Confidential
40
Rev. 3.0
Aug. /2014
ALSC [ ALLIANCE SEMICONDUCTOR CORPORATION ]
