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256Mb: x4, x8, x16 SDRAM
256MSDRAM_E.p65
–
Rev. E; Pub. 3/02
Micron Technology, Inc., reserves the right to change products or specifications without notice.
2002, Micron Technology, Inc.
256Mb: x4, x8, x16
SDRAM
ALTERNATING BANK WRITE ACCESSES
1
tCH
tCL
tCK
CLK
DQ
DON
’
T CARE
D
IN
m
tDH
tDS
D
IN
m
+ 1
D
IN
m
+ 2
D
IN
m
+ 3
COMMAND
tCMH
tCMS
NOP
NOP
ACTIVE
NOP
WRITE
NOP
NOP
ACTIVE
tDH
tDS
tDH
tDS
tDH
tDS
ACTIVE
WRITE
D
IN
b
tDH
tDS
D
IN
b
+ 1
D
IN
b
+ 3
tDH
tDS
tDH
tDS
ENABLE AUTO PRECHARGE
DQM/
DQML, DQMU
A0-A9, A11, A12
BA0, BA1
A10
tCMH
tCMS
tAH
tAS
tAH
tAS
tAH
tAS
ROW
ROW
ROW
ROW
ENABLE AUTO PRECHARGE
ROW
ROW
BANK 0
BANK 0
BANK 1
BANK 0
BANK 1
CKE
tCKH
tCKS
D
IN
b
+ 2
tDH
tDS
COLUMN
b
3
COLUMN
m
3
tRP - BANK 0
tRAS - BANK 0
t
RC - BANK 0
tRCD - BANK 0
t
t
RCD - BANK 0
tWR - BANK 0
WR - BANK 1
tRCD - BANK 1
t
RRD
T0
T1
T2
T3
T4
T5
T6
T7
T8
T9
NOTE:
1. For this example, the burst length = 4.
2. Requires one clock plus time (7ns or 7.5ns) with auto precharge or 14ns to 15ns with PRECHARGE.
3. x16: A9, A11, and A12 =
“
Don
’
t Care
”
x8: A11 and A12 =
“
Don
’
t Care
”
x4: A12 =
“
Don
’
t Care
”
*CAS latency indicated in parentheses.
-7E
-75
SYMBOL*
t
CMS
t
DH
t
DS
t
RAS
t
RC
t
RCD
t
RP
t
RRD
t
WR
MIN
1.5
0.8
1.5
37
60
15
15
14
Note 2
MAX
MIN
1.5
0.8
1.5
44
66
20
20
15
Note 2
MAX
UNITS
ns
ns
ns
ns
ns
ns
ns
ns
ns
120,000
120,000
TIMING PARAMETERS
-7E
-75
SYMBOL*
t
AH
t
AS
t
CH
t
CL
t
CK (3)
t
CK (2)
t
CKH
t
CKS
t
CMH
MIN
0.8
1.5
2.5
2.5
7
7.5
0.8
1.5
0.8
MAX
MIN
0.8
1.5
2.5
2.5
7.5
10
0.8
1.5
0.8
MAX
UNITS
ns
ns
ns
ns
ns
ns
ns
ns
ns