K4D261638F Datasheet, PDF (13/18 Pages) Samsung semiconductor – 128Mbit GDDR SDRAM

K4D261638F
128M GDDR SDRAM
AC CHARACTERISTICS - 1
Parameter
CK cycle time
CL=3
CL=4
CL=5
CK high level width
CK low level width
DQS out access time from CK
Output access time from CK
Data strobe edge to Dout edge
Read preamble
Read postamble
CK to valid DQS-in
DQS-In setup time
DQS-in hold time
DQS write postamble
DQS-In high level width
DQS-In low level width
Address and Control input setup
Address and Control input hold
DQ and DM setup time to DQS
DQ and DM hold time to DQS
Clock half period
Data output hold time from DQS
Symbol
tCK
tCH
tCL
tDQSCK
tAC
tDQSQ
tRPRE
tRPST
tDQSS
tWPRES
tWPREH
tWPST
tDQSH
tDQSL
tIS
tIH
tDS
tDH
tHP
tQH
-25
Min
Max
-
-
4
2.5
0.45
0.55
0.45
0.55
-0.55
0.55
-0.55
0.55
-
0.35
0.9
1.1
0.4
0.6
0.85
1.15
0
-
0.35
-
0.4
0.6
0.45
0.55
0.45
0.55
0.8
-
0.8
-
0.35
-
0.35
-
tCLmin
or
-
tCHmin
tHP-0.4
-
-2A
Min
Max
-
2.86
10
0.45
0.55
0.45
0.55
-0.6
0.6
-0.6
0.6
-
0.35
0.9
1.1
0.4
0.6
0.85
1.15
0
-
0.35
-
0.4
0.6
0.4
0.6
0.4
0.6
0.9
-
0.9
-
0.35
-
0.35
-
tCLmin
or
-
tCHmin
tHP-0.35
-
-33
Min
Max
-
3.3
10
0.45
0.55
0.45
0.55
-0.6
0.6
-0.6
0.6
-
0.35
0.9
1.1
0.4
0.6
0.85
1.15
0
-
0.35
-
0.4
0.6
0.4
0.6
0.4
0.6
0.9
-
0.9
-
0.35
-
0.35
-
tCLmin
or
-
tCHmin
tHP-0.35
-
Unit
ns
ns
ns
tCK
tCK
ns
ns
ns
tCK
tCK
tCK
ns
tCK
tCK
tCK
tCK
ns
ns
ns
ns
Note
1
ns
1
ns
1
Note 1 :
- The JEDEC DDR specification currently defines the output data valid window(tDV) as the time period when the data
strobe and all data associated with that data strobe are coincidentally valid.
- The previously used definition of tDV(=0.35tCK) artificially penalizes system timing budgets by assuming the worst
case
output vaild window even then the clock duty cycle applied to the device is better than 45/55%
- A new AC timing term, tQH which stands for data output hold time from DQS is difined to account for clock duty cycle
variation and replaces tDV
- tQHmin = tHP-X where
. tHP=Minimum half clock period for any given cycle and is defined by clock high or clock low time(tCH,tCL)
. X=A frequency dependent timing allowance account for tDQSQmax
- 13 -
Rev. 1.2 (Jan. 2004)