mt48h8m16lf Micron Semiconductor Products, mt48h8m16lf Datasheet - Page 67

• Manufacturer Part Number: mt48h8m16lf
• Description: 128mb 8 Meg X 16, 4 Meg X 32 Mobile Sdram
• Manufacturer: Micron Semiconductor Products

Figure 47:
Self Refresh
PDF: 09005aef832ff1ea / Source: 09005aef832ff1ac
sdr_mobile_sdram_cmd_op_timing_dia_fr5.08__4.fm - Rev. B 6/08 EN
Command
BA0, BA1
Address
DQM
CKE
A10
CLK
DQ
High-Z
Precharge all
Auto Refresh Mode
active banks
t CKS
t CMS
t AS
Single bank
PRECHARGE
All banks
Bank(s)
T0
Notes:
t AH
t CKH
t CMH
t CK
1. Back-to-back AUTO REFRESH commands are not required.
The self refresh mode can be used to retain data in the SDRAM, even if the rest of the
system is powered down. When in self refresh mode, the SDRAM retains data without
external clocking. The SELF REFRESH command is initiated like an AUTO REFRESH
command, except CKE is disabled (LOW). After the SELF REFRESH command is regis-
tered, all the inputs to the SDRAM become “Don’t Care” with the exception of CKE,
which must remain LOW.
After self refresh mode is engaged, the SDRAM provides its own internal clocking,
causing it to perform its own AUTO REFRESH cycles. The SDRAM must remain in self
refresh mode for a minimum period equal to
for an indefinite period beyond that.
t RP
T1
NOP
T2
REFRESH
AUTO
t CH
t RFC
128Mb: 8 Meg x 16, 4 Meg x 32 Mobile SDRAM
NOP
67
(
(
(
(
(
(
(
)
(
)
(
)
(
)
)
)
)
)
)
(
(
(
)
(
(
(
(
)
(
(
)
)
(
(
(
(
)
(
)
(
)
)
)
)
(
)
)
)
)
)
)
(
(
(
)
(
)
(
(
)
)
)
)
)
NOP
Micron Technology, Inc., reserves the right to change products or specifications without notice.
t CL
Tn + 1
REFRESH
t
AUTO
RAS and may remain in self refresh mode
t RFC
NOP
(
(
(
(
(
(
)
)
(
)
)
(
(
(
(
)
)
)
)
)
)
(
(
)
(
)
)
(
(
(
(
(
)
(
)
(
(
(
)
(
)
(
)
)
)
(
)
)
)
)
)
(
)
(
)
)
NOP
©2008 Micron Technology, Inc. All rights reserved.
Timing Diagrams
To + 1
ACTIVE
Row
Row
Bank
Don’t Care
Preliminary