HYB18M512160BFX Datasheet, PDF (37/52 Pages) Qimonda AG – DRAMs for Mobile Applications 512-Mbit DDR Mobile-RAM

CK
CK
CKE
CS
RAS
CAS
WE
A0-A12
BA0,BA1
= Don't Care
Figure 34 SELF REFRESH Entry Command
HYB18M512160BFX
512-Mbit DDR Mobile-RAM
Functional Description
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_XS 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.
CK
CK
t_RP
CKE
> t_RFC
t_XSR
t_RFC
Command PRE NOP
Address
A10 (AP)
DQ
Pre All
High-Z
ARF
NOP
NOP
NOP
ARF
NOP
ACT
Ba A,
Row n
Row n
Enter
Self Refresh
Mode
Figure 35 Self Refresh Entry and Exit
Exit from
Self Refresh
Mode
Any Command
(Auto Refresh
Recommended)
= Don't Care
Table 14 Timing Parameters for AUTO REFRESH and SELF REFRESH Commands
Parameter
Symbol
- 7.5 Unit Notes
Min. Max.
AUTO REFRESH to ACTIVE/AUTO REFRESH command period
PRECHARGE command period
Self refresh exit to next valid command delay
t_RFC
75
–
t_RP 22.5 –
t_XSR 120 –
ns ¹⁾
ns ¹⁾
ns ¹⁾
Refresh period
Average periodic refresh interval (8192 rows)
t_REF
t_REFI
– 64 ms –
–
7.8 µs ²⁾
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 to the next higher integer.
2) A maximum of eight AUTOREFRESH commands can be posted to the DDR Mobile-RAM device, meaning that the
maximum absolute interval between any Refresh command and the next Refresh command is 8 * tREFI.
Data Sheet
37
Rev. 1.10, 2006-11
04052006-4SYQ-ZRN3