EDS2504ACTA/08ACTA/16ACTA, EDS2504APTA/08APTA/16APTA
Refresh
Auto-refresh
All the banks must be precharged before executing an auto-refresh command. Since the auto-refresh command
updates the internal counter every time it is executed and determines the banks and the ROW addresses to be
refreshed, external address specification is not required. The refresh cycles are required to refresh all the ROW
addresses within tREF (max.). The output buffer becomes High-Z after auto-refresh start. In addition, since a
precharge has been completed by an internal operation after the auto-refresh, an additional precharge operation by
the precharge command is not required.
Self-refresh
After executing a self-refresh command, the self-refresh operation continues while CKE is held Low. During self-
refresh operation, all ROW addresses are refreshed by the internal refresh timer. A self-refresh is terminated by a
self-refresh exit command. Before and after self-refresh mode, execute auto-refresh to all refresh addresses in or
within tREF (max.) period on the condition 1 and 2 below.
1. Enter self-refresh mode within time as below* after either burst refresh or distributed refresh at equal interval to
all refresh addresses are completed.
2. Start burst refresh or distributed refresh at equal interval to all refresh addresses within time as below*after
exiting from self-refresh mode.
Note: tREF (max.) / refresh cycles.
Others
Power-down mode
The SDRAM enters power-down mode when CKE goes Low in the IDLE state. In power down mode, power
consumption is suppressed by deactivating the input initial circuit. Power down mode continues while CKE is held
Low. In addition, by setting CKE to High, the SDRAM exits from the power down mode, and command input is
enabled from the next clock. In this mode, internal refresh is not performed.
Clock suspend mode
By driving CKE to Low during a bank active or read/write operation, the SDRAM enters clock suspend mode. During
clock suspend mode, external input signals are ignored and the internal state is maintained. When CKE is driven
High, the SDRAM terminates clock suspend mode, and command input is enabled from the next clock. For details,
refer to the "CKE Truth Table".
Data Sheet E0110E30 (Ver. 3.0)
41
ELPIDA [ ELPIDA MEMORY ]
