EDD51323DBH-LS
CKE Truth Table
CKE
n − 1
H
Current state
Command
n
/CS
L
/RAS /CAS /WE
Address
Notes
Idle
Idle
Auto-refresh command (REF)
Self-refresh entry (SELF)
H
L
L
L
H
H
H
×
×
×
×
×
×
×
×
×
×
×
2
2
H
L
L
L
H
L
L
H
×
H
×
Active/Idle
Idle
Power-down entry (PDEN)
Deep power-down entry (DPDEN)
Self-refresh exit (SELFX)
H
L
H
L
H
L
H
H
×
H
H
×
L
L
H
H
H
H
H
L
H
×
Self-refresh
L
H
L
L
H
×
H
×
H
×
Power-down
Power-down exit (PDEX)
L
H
×
Deep power-down Power-down exit (DPDEX)
L
×
×
×
Notes: 1. H: VIH. L: VIL × : Don’t care.
2. All the banks must be in IDLE before executing this command.
3. The CKE level must be kept for 1 clock cycle at least.
Auto-refresh command [REF]
This command executes auto-refresh. The bank and the ROW addresses to be refreshed are internally determined
by the internal refresh controller. The output buffer becomes high-Z after auto-refresh start. Precharge has been
completed automatically after the auto-refresh. The ACT or MRS command can be issued tRFC after the last auto-
refresh command.
The average refresh cycle is 7.8µs. To allow for improved efficiency in scheduling, some flexibility in the absolute
refresh interval (64ms) is provided. A maximum of eight auto-refresh commands can be posted to the DDR Mobile
RAM or the maximum absolute interval between any auto-refresh command and the next auto-refresh command is
8 × tREF.
Self-refresh entry [SELF]
This command starts self-refresh. The self-refresh operation continues as long as CKE is held low. During the self-
refresh operation, all ROW addresses are repeated refreshing by the internal refresh controller. A self-refresh is
terminated by a self-refresh exit command.
Power-down mode entry [PDEN]
tPDEN after the cycle when [PDEN] is issued, the DDR Mobile RAM enters into power-down mode. In power-down
mode, power consumption is suppressed by deactivating the input initial circuit. Power-down mode continues while
CKE is held low. No internal refresh operation occurs during the power-down mode.
Deep power-down entry [DPDEN]
After the command execution, deep power-down mode continues while CKE remains low.
Before executing deep power-down, all banks must be precharged or in idle state.
Self-refresh exit [SELFX]
This command is executed to exit from self-refresh mode. tSREX after [SELFX], the device will be into idle state.
Power-down exit [PDEX]
The DDR Mobile RAM can exit from power-down mode tPDEX (1 cycle min.) after the cycle when [PDEX] is issued.
Preliminary Data Sheet E1432E20 (Ver. 2.0)
20
ELPIDA [ ELPIDA MEMORY ]
