MT47H64M8CF-25E IT:G Micron Technology Inc, MT47H64M8CF-25E IT:G Datasheet - Page 90

• Manufacturer Part Number: MT47H64M8CF-25E IT:G
• Description: 64MX8 DDR2 SDRAM PLASTIC IND TEMP FBGA 1.8V
• Manufacturer: Micron Technology Inc

ACTIVATE
Figure 42: Example: Meeting
PDF: 09005aef82f1e6e2
512MbDDR2.pdf - Rev. T 2/12 EN
Bank address
Command
Address
CK#
CK
Bank x
ACT
Row
T0
NOP
T1
Before any READ or WRITE commands can be issued to a bank within the DDR2
SDRAM, a row in that bank must be opened (activated), even when additive latency is
used. This is accomplished via the ACTIVATE command, which selects both the bank
and the row to be activated.
After a row is opened with an ACTIVATE command, a READ or WRITE command may
be issued to that row subject to the
by the clock period and rounded up to the next whole number to determine the earliest
clock edge after the ACTIVATE command on which a READ or WRITE command can be
entered. The same procedure is used to convert other specification limits from time
units to clock cycles. For example, a
clock (
which covers any case where 5 <
t
A subsequent ACTIVATE command to a different row in the same bank can only be is-
sued after the previous active row has been closed (precharged). The minimum time in-
terval between successive ACTIVATE commands to the same bank is defined by
A subsequent ACTIVATE 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 mini-
mum time interval between successive ACTIVATE commands to different banks is de-
fined by
DDR2 devices with 8 banks (1Gb or larger) have an additional requirement:
requires no more than four ACTIVATE commands may be issued in any given
(MIN) period, as shown in Figure 43 (page 91).
RRD where 2 <
t RRD
t
t
CK = 3.75ns) results in 5.3 clocks, rounded up to 6. This is shown in Figure 42,
RRD (MIN) and
t
NOP
RRD.
T2
t
RRD (MIN)/
Bank y
ACT
Row
T3
t
RCD (MIN)
NOP
t
T4
CK ≤ 3.
90
t
t RRD
t RCD
RCD (MIN)/
t
RCD specification.
t
RCD (MIN) specification of 20ns with a 266 MHz
NOP
T5
Micron Technology, Inc. reserves the right to change products or specifications without notice.
512Mb: x4, x8, x16 DDR2 SDRAM
t
CK ≤ 6. Figure 42 also shows the case for
Bank z
NOP
Row
T6
t
RCD (MIN) should be divided
NOP
T7
2004 Micron Technology, Inc. All rights reserved.
NOP
T8
ACTIVATE
t
FAW. This
RD/WR
Bank y
Col
t
Don’t Care
T9
FAW
t
RC.