mt48h8m16lf Micron Semiconductor Products, mt48h8m16lf Datasheet - Page 66

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

Figure 46:
AUTO 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
CLK
CKE
A10
DQ
t CMS
t CKS
t AS
t AS
t AS
ACTIVE
Row
Row
Bank
T0
Single WRITE – Without Auto Precharge
t CMH
t AH
t AH
t AH
t CKH
t RCD
t RAS
t RC
Notes:
t CK
T1
NOP
1. For this example, BL = 1 and the WRITE burst is followed by a manual PRECHARGE.
The AUTO REFRESH command is used during normal operation of the SDRAM to
refresh the contents of the SDRAM array. This command is non persistent, so it must be
issued each time a refresh is required. All active banks must be PRECHARGED prior to
issuing an AUTO REFRESH command. The AUTO REFRESH command should not be
issued until the minimum
generated by the internal refresh controller. This makes the address bits “Don’t Care”
during an AUTO REFRESH command. After the AUTO REFRESH command is initiated, it
must not be interrupted by any executable command until
t
edge of the clock. The LP-SDRAM requires that every row be refreshed each
Providing a distributed AUTO REFRESH command calculated by dividing the refresh
period (
ensure that each row is refreshed. Alternatively, a burst refresh can be employed after
every
rows to be refreshed at the minimum cycle rate (
ment.
RFC time, COMMAND INHIBIT or NOP commands must be issued on each positive
Disable auto precharge
t CMS
t CL
t
t DS
REF period, by issuing consecutive AUTO REFRESH commands for the number of
Column m
D
t
T2
WRITE
Bank
REF) by the number of rows to be refreshed, meets the timing requirement and
IN
m
t CH
t CMH
t DH
t WR
T3
NOP
t
128Mb: 8 Meg x 16, 4 Meg x 32 Mobile SDRAM
RP is met after the PRECHARGE command. Addressing is
66
T4
NOP
Single bank
Micron Technology, Inc., reserves the right to change products or specifications without notice.
All banks
PRECHARGE
Bank
T5
t
RFC), to satisfy the refresh require-
T6
t RP
NOP
t
RFC has been met. During
©2008 Micron Technology, Inc. All rights reserved.
Bank
Row
ACTIVE
T7
Timing Diagrams
T8
t
NOP
REF period.
Preliminary
Don’t Care