HY5FS123235AFCP Datasheet, PDF (19/74 Pages) Hynix Semiconductor – 512M (16Mx32) GDDR4 SDRAM

HY5FS123235AFCP
OPERATION
Deselect
(NOP)
The DESELECT function (CS# HIGH) prevents new
commands from being executed by the GDDR4 SDRAM.
The GDDR4 SDRAM is effectively deselected. Operations
already in progress are not affected.
No Operation (NOP)
The NO OPERATION (NOP) command is used to instruct
the selected GDDR4 SDRAM to perform a NOP (CS#
LOW). This prevents unwanted commands from being
registered during idle or wait states. Operations already in
progress are not affected.
MODE REGISTER SET
The mode registers are loaded via inputs A0 A12.
See mode register descriptions in the Register Definition
section. The MODE REGISTER SET command can only be
issued when all banks are idle, and a subsequent execut-
able command cannot be issued until t_MRD is met.
Activation
Before any READ or WRITE commands can be issued to
a bank in the GDDR4 SDRAM, a row in that bank must be
“opened”. This is accomplished by the ACTIVE command
(see Figure 8): BA0-BA2 select the bank, and the address
inputs select the row to be activated. Once a row is open,
a READ or WRITE command could be issued to that row,
subject to the t_RCD 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 de-
fined by t_RC.
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. Figure 9 shows the
t_RCD and t_RRD definition.
The row remains active until a PRECHARGE command (or
READ or WRITE command with Auto Precharge) is issued
to the bank.
A PRECHARGE command (or READ or WRITE command
with Auto Precharge) must be issued before opening a
different row in the same bank.
CK#
CK
CKE#
M ode Register Set
LOW
Row Activation
CK#
CK
CKE#
LOW
CS#
RAS#
CS#
RAS#
CAS#
CAS#
WE#
A 0 ,A 2 ,A 3 ,A 4 ,A 7
A8-A12
BA0,1,2
A1,A5,A6
CO
A8,9,10,11,12
BA
BA0,1,2
CO
A4,7,0,3,2
CO
A1,5,6
RA = Row Address
CO = Op-code
DONsT CARE
BA = Bank Address
EN AP = Enable Auto Precharge
DIS AP = D isable Auto Precharge
WE#
A0,A2,A3,A4,A7
A8-A12
BA0,1,2
A1,A5,A6
RA
A8,9,10,11,12
BA
BA0,1,2
RA
A4,7,0,3,2
RA
A1,5,6
RA = Row Address
CA = Colum n Address
DONsT CARE
BA = Bank Address
EN AP =Enable Auto Precharge
DIS AP = Disable Auto Precharge
Figure 7: MRS Command
Figure 8: ACTIVE command
Rev. 1.2 /June. 2008
19