W3EG72125S-D3

-JD3

-AJD3

November 2004

Rev. 2

PRELIMINARY

9

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

White Electronic Designs

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

DDR SDRAM COMPONENT ELECTRICAL CHARACTERISTICS AND

RECOMMENDED AC OPERATING CONDITIONS (continued)

AC Characteristics

335

262/263/265

202

Parameter

Symbol

Min

Max

Min

Max

Min

Max

Units

Notes

ACTIVE to READ or WRITE delay

18

20

20

ns

PRECHARGE command period

18

20

20

ns

DQS read preamble

0.9

1.1

0.9

1.1

0.9

1.1

19

DQS read postamble

0.4

0.6

0.4

0.6

0.4

0.6

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

10,11

DQS write postamble

0.4

0.6

0.4

0.6

0.4

0.6

9

Write recovery time

15

15

15

ns

Internal WRITE to READ command delay

111

Data valid output window

NA

ns

13

REFRESH to REFRESH command interval

70.3

70.3

70.3

μs

12

Average periodic refresh interval

7.8

7.8

7.8

μs

12

000

ns

Exit SELF REFRESH to non-READ command

75

75

80

ns

Exit SELF REFRESH to READ command

200

200

200