HY[B/E]18L256160B[C/F]X-7.5
256-Mbit Mobile-RAM
Functional Description
2.4.9.2
SELF REFRESH
The SELF REFRESH command can be used to retain
data in the Mobile-RAM, even if the rest of the system
is powered down. When in the self refresh mode, the
Mobile-RAM retains data without external clocking. The
SELF REFRESH command is initiated like an AUTO
REFRESH command except CKE is LOW. Input
signals except CKE are “Don’t Care” during SELF
REFRESH.
#,+
#+%
#3
2!3
#!3
7%
The procedure for exiting SELF REFRESH requires a
stable clock prior to CKE returning HIGH. Once CKE is
HIGH, NOP commands must be issued for tRC because
time is required for a completion of any internal refresh
in progress.
!ꢂꢎ!ꢀꢁ
"!ꢂꢏ"!ꢀ
If during normal operation burst auto refresh or user
controlled refresh is used, add 8192 auto refresh cycles
just before self refresh entry and just after self refresh
exit.
ꢒ $ONgT #ARE
Figure 43 SELF REFRESH Entry Command
#,+
T20
T2#
T2#
T32%8
#+%
02%
./0
!2&
./0
./0
./0
!2&
./0
!#4
#OMMAN
"A !ꢏ
!
RESS
2OW N
2OW N
!ꢀꢂ ꢌ!0ꢍ
$1
0RE !LL
(IGHꢎ:
ꢒ $ONgT #ARE
3ELF 2EFRESH
%NTRY #OMMAN
3ELF 2EFRESH
%XIT #OMMAN
%XIT FROM
3ELF 2EFRESH
!NY #OMMAN
ꢌ!UTO 2EFRESH
2ECOMMEN E ꢍ
Figure 44 Self Refresh Entry and Exit
Table 13
Timing Parameters for AUTO REFRESH and SELF REFRESH
Parameter
Symbol
- 7.5
Units
Notes
min.
67
19
–
max.
1)
1)
1)
1)
ACTIVE to ACTIVE command period
PRECHARGE command period
Refresh period (8192 rows)
Self refresh exit time
tRC
tRP
–
–
ns
ns
tREF
tSREX
64
–
ms
tCK
1
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
35
Rev. 1.11, 2007-01
07142005-CR47-RB2E
QIMONDA [ QIMONDA AG ]
