HY[B/E]18L256160B[C/F]X-7.5
256-Mbit Mobile-RAM
Functional Description
2.4.4
ACTIVE
Before any READ or WRITE commands can be issued
to a bank within the Mobile-RAM, a row in that bank
must be “opened” (activated). This is accomplished via
the ACTIVE command and addresses A0 - A12, BA0
and BA1 (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 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).
#,+
#+%
#3
ꢌ(IGHꢍ
2!3
#!3
7%
ꢒ $ONgT #ARE
The minimum time interval between successive
ACTIVE commands to the same bank is defined by tRC.
A subsequent ACTIVE command to another bank can
be issued while the first bank is being accessed, which
results in a reduction of total row-access overhead. The
minimum time interval between successive ACTIVE
!ꢂꢎ!ꢀꢁ
2!
"!
"! ꢒ "ANK ! RESS
2! ꢒ 2OW ! RESS
"!ꢂꢏ"!ꢀ
Figure 9
ACTIVE Command
commands to different banks is defined by tRRD
.
#,+
!#4
2/7
"! X
./0
!#4
./0
./0
2$ꢊ72
#/,
./0
#OMMAN
!ꢂꢎ!ꢀꢁ
2/7
"! Y
"! Y
"!ꢂꢏ "!ꢀ
T22$
T2#$
ꢒ $ONgT #ARE
Figure 10 Bank Activate Timings
Table 9
Timing Parameters for ACTIVE Command
Symbol
Parameter
- 7.5
Units
Notes
min.
max.
1)
1)
1)
ACTIVE to ACTIVE command period
ACTIVE to READ or WRITE delay
ACTIVE bank A to ACTIVE bank B delay
tRC
tRCD
tRRD
67
19
15
–
–
–
ns
ns
ns
1) These parameters account for the number of clock cycles and depend on the operating frequency as follows:
no. of clock cycles = specified delay / clock period; round up to next integer.
Data Sheet
16
Rev. 1.11, 2007-01
07142005-CR47-RB2E
QIMONDA [ QIMONDA AG ]
