EDE2116AEBG-8E-F Datasheet, PDF (28/73 Pages) Elpida Memory – 2G bits DDR2 SDRAM

EDE2116AEBG
CKE Truth Table
Current state*²
CKE
Previous
cycle (n-1)*¹
Current
cycle (n)^*1
Command(n)^*3
/CS, /RAS, /CAS, /WE Operation (n)^*3
Notes
Power-down
L
L
×
Maintain power-down
11, 13, 14
L
H
DESL or NOP
Power-down exit
4, 8, 11, 13
Self-refresh
L
L
×
Maintain self-refresh
11, 14
L
H
DESL or NOP
Self-refresh exit
4, 5, 9
Bank Active
H
L
DESL or NOP
Active power-down entry
4, 8, 10, 11, 13
All banks idle
H
L
DESL or NOP
Precharge power-down entry 4, 8, 10, 11, 13
H
L
SELF
Self-refresh entry
6, 9, 11, 13
Any state other than
listed above
H
H
Refer to the Command Truth Table
7
Remark: H: VIH. L: VIL. ×: Don’t care.
Notes: 1. CKE (n) 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 operation (n) is a result of Command (n).
4. All states and sequences not shown are illegal or reserved unless explicitly described elsewhere in this
document.
5. On self-refresh exit, [DESL] or [NOP] commands must be issued on every clock edge occurring during the
tXSNR period. Read commands may be issued only after tXSRD (200 clocks) is satisfied.
6. Self-refresh mode can only be entered from the all banks idle state.
7. Must be a legal command as defined in the command truth table.
8. Valid commands for power-down entry and exit are [NOP] and [DESL] only.
9. Valid commands for self-refresh exit are [NOP] and [DESL] only.
10. Power-down and self-refresh can not be entered while read or write operations, (extended) mode register
set operations or precharge operations are in progress. See section Power-Down and Self-Refresh
Command for a detailed list of restrictions.
11. Minimum CKE high time is 3 clocks; minimum CKE low time is 3 clocks.
12. The state of ODT does not affect the states described in this table. The ODT function is not available
during self-refresh. See section ODT (On Die Termination).
13. The power-down does not perform any refresh operations. The duration of power-down mode is therefore
limited by the refresh requirements outlined in section automatic refresh command.
14. “×” means “don’t care” (including floating around VREF) in self-refresh and power-down. However ODT
must be driven high or low in power-down if the ODT function is enabled (bit A2 or A6 set to 1 in
EMRS (1)).
Data Sheet E1820E21 (Ver.2.1)
28