HYB18M1G16 Datasheet, PDF (43/65 Pages) Qimonda AG – 1-Gbit x16 DDR Mobile-RAM

Data Sheet
HY[B/E]18M1G16[0/1]BF
1-Gbit DDR Mobile-RAM
FIGURE 34
Auto Refresh
CK
CK
Command
Address
PRE
t_RP
NOP
A10 (AP)
DQ
Pre All
High-Z
ARF
t_RFC
NOP
NOP
ARF
t_RFC
NOP
NOP
ACT
Ba A,
Row n
Row n
Ba A, Row n = Bank A, Row n
= Don't Care
2.4.9.2 SELF REFRESH
The SELF REFRESH command can be used to retain data in the DDR Mobile-RAM, even if the rest of the system is powered
down. When in the Self Refresh mode, the DDR Mobile-RAM retains data without external clocking. The DDR Mobile-RAM
device has a built-in timer to accommodate Self Refresh operation. 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 user may halt
the external clock one clock after Self Refresh entry is registered.
FIGURE 35
SELF REFRESH Entry Command
CK
CK
CKE
CS
RAS
CAS
WE
A0-A12
BA0,BA1
Once the command is registered, CKE must be held low to
keep the device in Self Refresh mode. The device executes a
minimum of one AUTO REFRESH command internally once
it enters Self Refresh mode. The clock is internally disabled
during Self Refresh operation to save power. The minimum
time that the device must remain in Self Refresh mode is t_RFC.
The procedure for exiting Self Refresh requires a sequence of
commands. First, the clock must be stable prior to CKE going
back HIGH. Once Self Refresh Exit is registered, a delay of at
least t_XSR must be satisfied before a valid command can be
issued to the device to allow for completion of any internal
refresh in progress.The use of Self Refresh mode introduces
the possibility that an internally timed refresh 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.
= Don't Care
Rev.1.0, 2007-03
43
10242006-Y557-TZXW