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White Electronic Designs Corporation • (602) 437-1520 • www.wedc.com

White Electronic Designs

W3EG6466S-AD4

-BD4

January 2005

Rev. 2

White Electronic Designs Corp. reserves the right to change products or specifications without notice.

PRELIMINARY

DDR SDRAM COMPONENT ELECTRICAL CHARACTERISTICS AND RECOMMENDED AC

OPERATING CONDITIONS (Continued)

AC CHARACTERISTICS

335

262

265/202

UNITS

NOTES

PARAMETER

SYMBOL

MIN

MAX

MIN

MAX

MIN

MAX

DQ-DQS hold, DQS to first DQ to go non-valid, per access

ns

22, 23

Data hold skew factor

0.75

0.75

0.75

ns

ACTIVE to PRECHARGE command

42

70,000

40

120,000

40

120,000

ns

31, 47

ACTIVE to READ with Auto precharge command

15

15

20

ns

ACTIVE to ACTIVE/AUTO REFRESH command period

60

60

65

ns

AUTO REFRESH command period

72

75

75

ns

42

ACTIVE to READ or WRITE delay

15

15

20

ns

PRECHARGE command period

15

15

20

ns

DQS read preamble

0.9

1.1

0.9

1.1

0.9

1.1

37

DQS read postamble

0.4

0.6

0.4

0.6

0.4

0.6

37

ACTIVE bank a to ACTIVE bank b command

12

15

15

ns

DQS write preamble

0.25

0.25

0.25

DQS write preamble setup time

0

0

0

ns

18, 19

DQS write postamble

0.4

0.6

0.4

0.6

0.4

0.6

17

Write recovery time

15

15

15

ns

Internal WRITE to READ command delay

111

Data valid output window

NA

ns

22

REFRESH to REFRESH command interval

70.3

70.3

70.3

µs

21

Average periodic refresh interval

7.8

7.8

7.8

µs

21

Terminating voltage delay to VDD

000

ns

Exit SELF REFRESH to non-READ command

75

75

75

ns

Exit SELF REFRESH to READ command

200

200

200