W949D6DB Datasheet, PDF (27/60 Pages) Winbond – Standard Self Refresh Mode

W949D6DB / W949D2DB
8.4 Active
Before any READ or WRITE commands can be issued to a bank in the LPDDR SDRAM, a row in that
bank must be opened. This is accomplished by the ACTIVE command: BA0 and BA1 select the bank,
and the address inputs select the row to be activated. More than one bank can be active at any time.
Once a row is open, a READ or WRITE command could be issued to that row, subject to the tRCD
specification.
A subsequent ACTIVE command to another row in the same bank can only be issued after the previous
row has been closed. The minimum time interval between two successive ACTIVE commands on the
same bank is defined by tRC.
A subsequent ACTIVE command to another bank can be issued while the first bank is being accessed,
which results in a reduction of total row-access overhead. The minimum time interval between two
successive ACTIVE commands on different banks is defined by tRRD.
The row remains active until a PRECHARGE command (or READ or WRITE command with Auto
Precharge) is issued to the bank.
A PRECHARGE (or READ with Auto Precharge or Write with Auto Precharge) command must be issued
before opening a different row in the same bank.
8.4.1 Active Command
CK
CK
CKE
CS
(High)
RAS
CAS
WE
Address
RA
BA0,BA1
BA
= Don't Care
BA = Bank Address
RA = Row Address
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Publication Release Date: Oct. 08, 2014
Revision: A01-003