256Mb: x4, x8, x16 SDRAM
AUTO REFRESH Operation
Figure 52: Auto Refresh Mode
T0
CLK
tCK
T1
T2
tCH
((
))
((
))
((
))
tCL
Tn + 1
((
))
((
))
((
))
To + 1
CKE
tCKS
tCMS
tCKH
tCMH
NOP
AUTO
REFRESH
Command
PRECHARGE
((
))
NOP
( (
NOP
))
((
))
((
))
((
))
((
))
AUTO
REFRESH
((
))
NOP
( (
NOP
))
((
))
((
))
((
))
((
))
((
))
((
))
ACTIVE
DQM
Address
All banks
Row
A10
Single bank
tAS
tAH
((
))
((
))
Row
BA0, BA1
Bank(s)
((
))
((
))
((
))
tRP
tRFC
tRFC
((
))
((
))
((
))
Bank
DQ
High-Z
Precharge all
active banks
Don’t Care
Note:
1. Back-to-back AUTO REFRESH commands are not required.
PDF: 09005aef8091e6d1
256Mb_sdr.pdf - Rev. S 12/12 EN
80
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©
1999 Micron Technology, Inc. All rights reserved.
MICRON [ MICRON TECHNOLOGY ]
