K4H280438B-TCA0 Datasheet, PDF (45/53 Pages) Samsung semiconductor – 128Mb DDR SDRAM

128Mb DDR SDRAM
Parameter
-A2(PC266@CL=2) -B0(PC266@CL=2.5) -A0(PC200@CL=2)
Symbol
Unit Note
Min
Max
Min
Max
Min
Max
Exit self refresh to bank active command tXSA
75
75
80
ns 7
Exit self refresh to read command
tXSR
200
200
200
Cycle
Refresh interval time 64Mb, 128Mb
15.6
tREF
256Mb
7.8
15.6
7.8
15.6
7.8
us 1
us 1
Output DQS valid window
tQH
tHPmin
-0.75ns
-
tHPmin
-0.75ns
-
tHPmin
-1.0ns
-
ns
Clock half period
tHP
tCLmin
or tCHmin
-
tCLmin
or tCHmin
-
tCLmin
or tCHmin
-
ns
DQS write postamble time
tWPST
0.25
0.25
0.25
tCK 4
QFC setup to first DQS edge on reads tQCS
0.9
1.1
0.9
1.1
0.9
1.1 tCK
QFC hold after last DQS edge on reads tQCH
0.4
0.6
0.4
0.6
0.4
0.6 tCK
Write command to QFC delay on write tQCSW
4.0
4.0
4.0
ns
Write burst end to QFC delay on write tQCHW
1.25ns 0.5tCK 1.25ns 0.5tCK 1.25ns 0.5tCK
5
Write burst end to QFC delay on write
interrupted by Precharge
tQCHWI
-
1.5tCK
-
1.5tCK
-
1.5tCK
6
1. Maximum burst refresh of 8
2. tHZQ transitions occurs in the same access time windows as valid data transitions. These parameters are not referenced
to a specific voltage level, but specify when the device output is no longer driving.
3. The specific requirement is that DQS be valid(High or Low) on or before this CK edge. The case shown(DQS going from
High_Z to logic Low) applies when no writes were previously in progress on the bus. If a previous write was in progress,
DQS could be High at this time, depending on tDQSS.
4. The maximum limit for this parameter is not a device limit. The device will operate with a great value for this parameter,
but system performance (bus turnaround) will degrade accordingly.
5. The value of tQCSW min. is 1.25ns from the last low going data strobe edge to QFC high. And the value of
tQCSW max. is 0.5tcK from the first high going clock edge after the last low going data strobe edge to QFC
high.
6. the value of tQCSWI max. is 1.5tcK from the first high going clock edge after the last low going data strobe
edge to QFC high.
7. A write command can be applied with tRCD satisfied after this command.
Table 14. AC timing parameters and specifications
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REV. 1.0 November. 2. 2000