K4J52324QC Datasheet, PDF (44/57 Pages) Samsung semiconductor – 512Mbit GDDR3 SDRAM

K4J52324QC-B
PRECHARGE
The PRECHARGE command is used to deactivate the open row in a
particular bank or the open row in all banks. The bank(s) will be available
for a subsequent row access some specified time (t_RP) after the PRE-
CHARGE command is issued. Input A8 determines whether one or all
banks are to be precharged, and in the case where only one bank is to
be precharged, inputs BA0, BA1, BA2 select the bank. When all banks
are to be precharged, inputs BA0, BA1, BA2 are treated as "Don’t Care."
Once a bank has been precharged, it is in the idle state and must be acti-
vated prior to any READ or WRITE commands being issued to the bank.
512M GDDR3 SDRAM
/CK
CK
CKE
/CS
/RAS
HIGH
POWER-DOWN (CKE NOT ACTIVE)
Unlike SDR SDRAMs,GDDR3(x32) SDRAM requires CKE to be active
at all times an access is in progress; from the issuing of a READ or
WRITE command until completion of the burst. For READs, a burst com-
pletion is defined when the Read Postamble is satisfied; For WRITEs, a
burst completion is defined BL/2 cycles after the Write Postamble is sat-
isfied.
Power-down is entered when CKE is registered LOW. If power-down
occurs when there is a row active in any bank, this mode is referred to as
active power-down. Entering power-down deactivates the input and out-
put buffers, excluding CK,/CK and CKE. For maximum power savings,
the user has the option of disabling the DLL prior to entering power-
down. However, power-down duration is limited by the refresh require-
ments of the device, so in most applications,the self-refresh mode is pre-
ferred over the DLL-disabled power-down mode.
When in power-down, CKE LOW and a stable clock signal must be
maintained at the inputs of the GDDR3 SDRAM, while all other input sig-
nals are "Don’t Care" except data terminator disable command.
The power-down state is synchronously exited when CKE is registered
HIGH (in conjunction with a NOP or DESELECT command). A valid exe-
cutable command may be applied tPDEX later.
/CAS
/WE
A0-A7, A9-A11
ALL BANKS
A8
ONE BANK
BA0,1,2
BA
DON’T CARE
BA=Bank Address
(if A8 is LOW; otherwise "Don’t Care")
PRECHARGE Command
Power-Down
T0
T1
T2
Ta0
Ta1
Ta2
Ta7
/CK
CK
t_IS
CKE
t_IS
t_PDEX
COMMAND
VALID
No PEAD/WRITE
access in progress
NOP
* Enter power - down mode
NOP
NOP
VALID
Exit power - down mode
* Once the device enters the power down mode, it should be in NOP state at least for 10ns
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Rev 1.0 (Mar 2005)