WED3EG7232S-JD3
PRELIMINARY
DDR SDRAM COMPONENT ELECTRICAL CHARACTERISTICS AND
RECOMMENDED AC OPERATING CONDITIONS (continued)
DDR400: V
CC
= V
CCQ
= +2.6V ± 0.1V; DDR333, 266, 200: V
CC
= V
CCQ
= +2.5V ± 0.2V
AC Characteristics
Parameter
ACTIVE to READ or WRITE delay
PRECHARGE command period
DQS read preamble
DQS read postamble
ACTIVE bank a to ACTIVE bank b command
DQS write preamble
DQS write preamble setup time
DQS write postamble
Write recovery time
Internal WRITE to READ command delay
Data valid output window
REFRESH to REFRESH command interval
Average periodic refresh interval
Terminating voltage delay to V
CC
Exit SELF REFRESH to non-READ command
Exit SELF REFRESH to READ command
Symbol
t
RCD
t
RP
t
RPRE
t
RPST
t
RRD
t
WPRE
t
WPRES
t
WPST
t
WR
t
WTR
NA
t
REFC
t
REFI
t
VTD
t
XSNR
t
XSRD
0
70
200
Min
15
15
0.9
0.4
10
0.25
0
0.4
15
2
t
QH
-t
DQSQ
70.3
7.8
0
75
200
0.6
1.1
0.6
403
Max
Min
15
15
0.9
0.4
12
0.25
0
0.4
15
1
t
QH
-t
DQSQ
70.3
7.8
0
75
200
0.6
1.1
0.6
335
Max
262/265
Min
15
15
0.9
0.4
15
0.25
0
0.4
15
1
t
QH
-t
DQSQ
70.3
7.8
0
75
200
0.6
1.1
0.6
Max
Min
20
20
0.9
0.4
15
0.25
0
0.4
15
1
t
QH
-t
DQSQ
70.3
7.8
0.6
1.1
0.6
202
Max
Units
ns
ns
t
CK
t
CK
ns
t
CK
ns
t
CK
ns
t
CK
ns
μs
μs
ns
ns
t
CK
13
12
12
10,11
9
Notes
June 2006
Rev. 6
8
White Electronic Designs Corporation • (602) 437-1520 • www.wedc.com
WEDC [ WHITE ELECTRONIC DESIGNS CORPORATION ]
