HYB18M1G320BF Datasheet, PDF (20/62 Pages) Qimonda AG – DRAMs for Mobile Applications 1-Gbit x32 DDR Mobile-RAM

Data Sheet
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 9),
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 t_RCD 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).
The minimum time interval between successive ACTIVE
commands to the same bank is defined 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 successive ACTIVE commands to different banks is
defined by t_RRD.
HY[B/E]18M1G320BF
1-Gbit DDR Mobile-RAM
FIGURE 9
ACTIVE Command
CK
CK
CKE
CS
RAS
CAS
WE
A0-A12
BA0,BA1
(High)
RA
BA
= Don't Care
BA = Bank Address
RA = Row Address
CK
CK
Command
A0-A12
BA0, BA1
ACT
Row
BA x
NOP
t_RRD
ACT
Row
BA y
FIGURE 10
Bank Activate Timings
NOP
NOP
t_RCD
RD/WR
Col
BA y
NOP
= Don't Care
Rev.1.00, 2007-03
20
02022006-J7N7-GYFP