K4J55323QG Datasheet, PDF (44/53 Pages) Samsung semiconductor – 256Mbit GDDR3 SDRAM

K4J55323QG
256M GDDR3 SDRAM
3. Current state definitions :
Idle : The bank has been precharged, and t_RP has been met.
Row Active : A row in the bank has been activated, and t_RCD has been met.
No data bursts/accesses and no register accesses are in progress.
Read : A READ burst has been initiated, with auto precharge disabled.
Write : A WRITE burst has been initiated, with auto precharge disabled.
Read w/ Auto- : See following text
Precharge Enabled
Write w/ Auto- : See following text
Precharge Enabled
3a. The read with auto precharge enabled or write with auto precharge enabled states can each be broken into two parts : the access period and the
precharge period. For read with auto precharge, the precharge period is defined as if the same burst was executed with auto precharge disabled
and then followed with the earliest possible PRECHARGE command that still accesses all of the data in the burst. For write with auto precharge, the
precharge period begins when tWR ends, with tWR command and ends where the precharge period (or t_RP) begins. During the precharge period of
the read with auto precharge enabled or write with auto precharge enabled states, ACTIVE, PRECHARGE, READ and WRITE commands to the
other bank may be applied. In either case, all other related Limitations apply (e.g., contention between read data write data must be avoided).
3b. The minimum delay from a READ or WRITE command with auto precharge enabled, to a command to a different bank is summarized below.
From Command
WRITE w/AP
READ w/AP
To Command
READ or READ w/AP
WRITE or WRITE w/AP
PRECHARGE
ACTIVE
READ or READ w/AP
WRITE or WRITE w/AP
PRECHARGE
ACTIVE
Minimum delay (with concurrent auto precharge)
[WL + (BL/2)] tCK + tWR
(BL/2) * tCK
1 tCK
1 tCK
(BL/2) * tCK
[CLRU + (BL/2)] + 1 - WL * tCK
1 tCK
1 tCK
4. AUTO REFRESH and LOAD MODE REGISTER commands may only be issued when all banks are idle.
5. All states and sequences not shown are illegal or reserved.
6. READs or WRITEs listed in the Command/Action column include READs or WRITEs with auto precharge enabled and READs or WRITEs with auto
precharge disabled.
7. Requires appropriate DM masking.
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Rev. 1.1 November 2005