W949D6DB Datasheet, PDF (47/60 Pages) Winbond – Standard Self Refresh Mode

W949D6DB / W949D2DB
8.13 Deep Power Down
The Deep Power-Down (DPD) mode enables very low standby currents. All internal voltage generators
inside the LPDDR SDRAM are stopped and all memory data is lost in this mode. All the information in
the Mode Register and the Extended Mode Register is lost.
Deep Power-Down is entered using the BURST TERMINATE command except that CKE is registered
Low. All banks must be in idle state with no activity on the data bus prior to entering the DPD mode.
While in this state, CKE must be held in a constant Low state.
To exit the DPD mode, CKE is taken high after the clock is stable and NOP commands must be
maintained for at least 200μs. After 200μs a complete re-initialization is required following steps 4
through 11 as defined for the initialization sequence.
8.13.1 Deep Power-Down Entry and Exit
T0
T1
CK
CK
CKE
Ta0
Ta1
Ta2
Command
NOP
DPD
NOP
Valid
Address
Valid
DQS
DQ
DM
t_RP
Enter DPD Mode
T = 200 µs
Exit DPD Mode
1) Clock must be stable before exiting Deep Power-Down mode. That is, the clock must be cycling
within specifications by Ta0
2) Device must be in the all banks idle state prior to entering Deep Power-Down mode
3) 200µs is required before any command can be applied upon exiting Deep Power-Down mode
4) Upon exiting Deep Power-Down mode a PRECHARGE ALL command must be issued, followed
by two AUTO REFRESH commands and a load mode register sequence
= Don't Care
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Publication Release Date: Oct. 08, 2014
Revision: A01-003