Internet Data Sheet
HYB25DC512[800/160]C[E/F]
512-Mbit Double-Data-Rate SDRAM
TABLE 11
Truth Table 2: Clock Enable (CKE)
Current State CKE n-1
CKEn
Command n
Action n
Note
Previous
Cycle
Current
Cycle
1)
2)
Self Refresh
Self Refresh
Power Down
Power Down
All Banks Idle
All Banks Idle
Bank(s) Active
L
L
X
Maintain Self-Refresh
Exit Self-Refresh
L
H
L
Deselect or NOP
X
L
Maintain Power-Down
Exit Power-Down
L
H
L
Deselect or NOP
Deselect or NOP
AUTO REFRESH
Deselect or NOP
See Table 12
H
H
H
H
Precharge Power-Down Entry
Self Refresh Entry
Active Power-Down Entry
–
L
L
H
1)
VREF must be maintained during Self Refresh operation
2) Deselect or NOP commands should be issued on any clock edges occurring during the Self Refresh Exit (tXSNR) period. A minimum of 200
clock cycles are needed before applying a read command to allow the DLL to lock to the input clock.
1. CKEn is the logic state of CKE at clock edge n: CKE n-1 was the state of CKE at the previous clock edge.
2. Current state is the state of the DDR SDRAM immediately prior to clock edge n.
3. COMMAND n is the command registered at clock edge n, and ACTION n is a result of COMMAND n.
4. All states and sequences not shown are illegal or reserved.
TABLE 12
Truth Table 3: Current State Bank n - Command to Bank n (same bank)
Current State CS
RAS CAS WE Command
Action
Note
1)2)3)4)5)6)
Any
H
L
L
L
L
X
H
L
L
L
X
H
H
L
X
H
H
H
L
Deselect
NOP. Continue previous operation.
1) to 6)
1) to 6)
1) to 7)
1) to 7)
No Operation
Active
NOP. Continue previous operation.
Idle
Select and activate row
AUTO REFRESH
–
–
L
MODE REGISTER
SET
1) to 6), 8)
1) to 6), 8)
1) to 6), 9)
1) to 6), 8)
1) to 6), 9)
1) to 6), 10)
Row Active
L
L
L
L
L
L
H
H
L
L
H
L
Read
Select column and start Read burst
Select column and start Write burst
Deactivate row in bank(s)
L
Write
H
L
L
Precharge
Read
Read (Auto
Precharge
Disabled)
H
L
H
L
Select column and start new Read burst
Truncate Read burst, start Precharge
BURST TERMINATE
H
H
Precharge
H
L
BURST
TERMINATE
1) to 6), 8), 11)
1) to 6), 8)
Write (Auto
Precharge
Disabled)
L
L
L
H
H
L
L
L
H
H
L
Read
Select column and start Read burst
Select column and start Write burst
Truncate Write burst, start Precharge
Write
1) to 6), 9), 11)
L
Precharge
1) This table applies when CKE n-1 was HIGH and CKE n is HIGH (see Table 11 and after tXSNR/tXSRD has been met (if the previous state
was self refresh).
Rev. 1.3, 2006-12
16
03292006-W2FE-ELDX
QIMONDA [ QIMONDA AG ]
