16

Integrated Silicon Solution, Inc. — www.issi.com

Rev. 00A

6/4/2013

IS43/46DR81280C, IS43/46DR16640C

Electrical Characteristics & AC Timing Specifications

Refresh parameters (TOPER; VDDQ = 1.8 V +/- 0.1 V; VDD = 1.8 V +/- 0.1 V)

Parameter

Symbol

Units

Notes

Refresh to active/Refresh command time

tRFC

127.5

ns

1

Average periodic refresh interval

tREFI

7.8

ms

1,2

7.8

ms

1

3.9

ms

1,2

3.9

ms

1,2,3

Notes:

1. If refresh timing is violated, data corruption may occur and the data must be re-written with valid data before a valid READ can be executed.

Note:

Each of the -25D and -3D speed options is individually backward compatible with all the timing specifications for slower options (ie. -25D

complies with specifications for -25D, -25E, -3D, -37C, -5B). -25E, -37C, and -5B shown for reference only.

Key Timing Parameters by Speed Grade

-25D

-25E

-3D

-37C

-5B

Speed bin (JEDEC)

DDR2-800D

DDR2-800E

DDR2-667D

DDR2-533C

DDR2-400B

CL-tRCD-tRP

5-5-5

6-6-6

5-5-5

4-4-4

3-3-3

tRCD

12.5

15

15

15

15

tRP

12.5

15

15

15

15

tRC

55

55

55

55

55

tRAS

40

40

40

40

40

tCK(avg)@CL=3

5

5

5

5

5

tCK(avg)@CL=4

3.75

3.75

3.75

3.75

5

tCK(avg)@CL=5

2.5

3

3

–

–

tCK(avg)@CL=6

2.5

2.5

–

–

–