HYB18L128160BF Datasheet, PDF (41/53 Pages) Infineon Technologies AG – DRAMs for Mobile Applications

2.4.9.2 SELF REFRESH
HY[B/E]18L128160B[C/F]-7.5
128-Mbit Mobile-RAM
Functional Description
CLK
CKE
CS
RAS
CAS
WE
A0-A11
BA0,BA1
= Don't Care
Figure 43 SELF REFRESH Entry Command
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.
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 t_RC because time is required for a completion of any internal refresh in
progress.
The use of SELF REFRESH mode introduces the possibility that an internally timed event can be missed when
CKE is raised for exit from SELF REFRESH mode. Upon exit from SELF REFRESH an extra AUTO REFRESH
command is recommended.
CLK
t_RP
> t_RC
t_RC
t_RC
t_SREX
CKE
Command PRE
NOP
ARF
Address
A10 (AP) _{Pre All}
DQ
High-Z
NOP
NOP
NOP
ARF
NOP
ACT
Ba A,
Row n
Row n
Self Refresh
Self Refresh
Entry Command Exit Command
Figure 44 Self Refresh Entry and Exit
Exit from
Self Refresh
Any Command
(Auto Refresh
Recommended)
= Don't Care
Data Sheet
41
V1.4, 2004-04-30