W3EG7232S-AD4 Datasheet, PDF (8/14 Pages) White Electronic Designs Corporation – 256MB - 32Mx72 DDR SDRAM UNBUFFERED w/PLL

White Electronic Designs
W3EG7232S-AD4
-BD4
PRELIMINARY
ELECTRICAL CHARACTERISTICS AND RECOMMENDED AC OPERATING CONDITIONS (Continued)
AC CHARACTERISTICS
PARAMETER
DQ-DQS hold, DQS to first DQ to go nonvalid, per
access
Data Hold Skew Factor
ACTIVE to PRECHARGE command
ACTIVE to READ with Auto precharge command
ACTIVE to ACTIVE/AUTO REFRESH command
period
AUTO REFRESH command period
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 (DVW)
REFRESH to REFRESH command interval
Average periodic refresh interval
Terminating voltage delay to VCC
Exit SELF REFRESH to non-READ command
Exit SELF REFRESH to READ command
335
262
265
202
SYMBOL MIN MAX MIN MAX MIN MAX MIN MAX UNITS NOTES
tQH tHP - tQHS
tHP - tQHS
tHP - tQHS
tHP - tQHS
ns 22, 23
tQHS
0.5
0.75
0.75
0.75 ns
tRAS 42 70,000 40 120,000 40 120,000 40 120,000 ns 31, 47
tRAP
15
15
15
20
ns
tRC
60
60
60
65
ns
tRFC
72
75
75
75
tRCD
15
15
15
20
tRP
15
15
15
20
tRPRE 0.9 1.1 0.9 1.1 0.9 1.1 0.9 1.1
tRPST 0.4 0.6 0.4 0.6 0.4 0.6 0.4 0.6
tRRD
12
15
15
15
tWPRE 0.25
0.25
0.25
0.25
tWPRES
0
0
0
0
tWPST 0.4 0.6 0.4 0.6 0.4 0.6 0.4 0.6
tWR
15
15
15
15
tWTR
1
1
1
1
na
tQH - tDQSQ
tQH - tDQSQ
tREFC
70.3
70.3
70.3
70.3
tREFI
7.8
7.8
7.8
0
7.8
tVTD
0
0
0
0
tXSNR
75
75
75 75
tXSRD 200
200
200 200
ns
ns
ns
tCK
37
tCK
37
ns
tCK
ns 18, 19
tCK
17
ns
tCK
ns 22
µs 21
µs
ns
ns
tCK
August 2005
Rev. 4
8
White Electronic Designs Corporation • [phone] • www.wedc.com