Data Sheet
HY[B/E]18M1G16[0/1]BF
1-Gbit DDR Mobile-RAM
2.4.4
ACTIVE
Before any READ or WRITE commands can be issued to a
bank within the DDR Mobile-RAM, a row in that bank must be
“opened” (activated). This is accomplished via the ACTIVE
command and addresses BA0, BA1, A0 - A12 (see
Figure 10), which decode and select both the bank and the
row to be activated. After opening a row (issuing an ACTIVE
command), a READ or WRITE command may be issued to
that row, subject to the tRCD specification. A subsequent
ACTIVE command to a different row in the same bank can
only be issued after the previous active row has been “closed”
(precharged).
FIGURE 10
ACTIVE Command
CK
CK
CKE
(High)
CS
The minimum time interval between successive ACTIVE
commands to 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 successive ACTIVE commands to different banks is
RAS
CAS
WE
A0-A12
BA0,BA1
RA
BA
defined by tRRD
.
= Don't Care
BA = Bank Address
RA = Row Address
FIGURE 11
Bank Activate Timings
CK
CK
Command
A0-A12
ACT
Row
BA x
NOP
ACT
Row
BA y
NOP
NOP
RD/WR
NOP
Col
BA0, BA1
BA y
tRRD
tRCD
= Don't Care
Rev.1.0, 2007-03
21
10242006-Y557-TZXW
QIMONDA [ QIMONDA AG ]
