W632GU6NB
Publication Release Date: Aug. 20, 2018
Revision: A01
- 97 -
9.2 CKE Truth Table
Notes 1-7 apply to the entire CKE Truth Table.
For Power-down entry and exit parameters See 8.17
on page 70.
CKE low is allowed only if t
MRD
and t
MOD
are satisfied.
Table 15
– CKE Truth Table
CURRENT
STATE
2
CKE
COMMAND (N)
3
RAS#,
CAS#,
WE#,
CS#
ACTION (N)
3
NOTES
Previous Cycle
1
(N-1)
Current Cycle
1
(N)
Power Down
L
L
X
Maintain Power Down
14,15
L
H
DESELECT or NOP
Power Down Exit
11,14
Self Refresh
L
L
X
Maintain Self Refresh
15,16
L
H
DESELECT or NOP
Self Refresh Exit
8,12,16
Bank(s) Active
H
L
DESELECT or NOP
Active Power Down Entry
11,13,14
Reading
H
L
DESELECT or NOP
Power Down Entry
11,13,14,17
Writing
H
L
DESELECT or NOP
Power Down Entry
11,13,14,17
Precharging
H
L
DESELECT or NOP
Power Down Entry
11,13,14,17
Refreshing
H
L
DESELECT or NOP
Precharge Power Down Entry
11
All Banks Idle
H
L
DESELECT or NOP
Precharge Power Down Entry
11,13,14,18
H
L
REFRESH
Self Refresh
9,13,18
Any other state
Refer to section 9.1
on page 95 for more detail with all command signals
10
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 defined as the state of the DDR3L 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), ODT is not included
here.
4. All states and sequences not shown are illegal or reserved unless explicitly described elsewhere in this document.
5. The state of ODT does not affect the states described in this table. The ODT function is not available during Self Refresh.
6. During any CKE transition (registration of CKE H->L or CKE L->H) the CKE level must be maintained until 1nCK prior to t
CKE
min
being satisfied (at which time CKE may transition again).
7. DESELECT and NOP are defined in the Command Truth Table.
8. On Self Refresh Exit DESELECT or NOP commands must be issued on every clock edge occurring during the t
XS
period. Read
or ODT commands may be issued only after t
XSDLL
is satisfied.
9. Self Refresh mode can only be entered from the All Banks Idle state.
10. Must be a legal command as defined in the Command Truth Table.
11. Valid commands for Power Down Entry and Exit are NOP and DESELECT only.
12. Valid commands for Self Refresh Exit are NOP and DESELECT only.
13. Self Refresh cannot be entered during Read or Write operations. For a detailed list of restrictions See section 8.16
on page 68 and See section 8.17
on page 70.
14. The Power Down does not perform any refresh operations.
15.
“X” means “don't care” (including floating around V
REF
) in Self Refresh and Power Down. It also applies to Address pins.
16. V
REF
(Both V
REFDQ
and V
REFCA
) must be maintained during Self Refresh operation.
V
REFDQ
supply may be turned OFF and
V
REFDQ
may take any value between V
SS
and V
DD
during Self Refresh operation, provided that V
REFDQ
is valid and stable prior
to CKE going back High and that first Write operation or first Write Leveling Activity may not occur earlier than 512 nCK after exit
from Self Refresh.
17. If all banks are closed at the conclusion of the read, write or precharge command, then Precharge Power Down is entered,
otherwise Active Power Down is entered.
18.
‘Idle state’ is defined as all banks are closed (t
RP
, t
DAL
, etc. satisfied), no data bursts are in progress, CKE is high, and all timings
from previous operations are satisfied (t
MRD
, t
MOD
, t
RFC
, t
ZQinit
, t
ZQ
oper, t
ZQCS
, etc.) as well as all Self Refresh exit and Power
Down Exit parameters are satisfied (t
XS
, t
XP
, t
XPDLL
, etc).