k4d263238d Samsung Semiconductor, Inc., k4d263238d Datasheet - Page 14

• Manufacturer Part Number: k4d263238d
• Description: 1m X 32bit X 4 Banks Double Data Rate Synchronous Dram With Bi-directional Data Strobe And Dll
• Manufacturer: Samsung Semiconductor, Inc.

tQH Timing (CL3, BL2)
K4D263238D
Note 1 :
- A new AC timing term, tQH which stands for data output hold time from DQS is defined to account for clock duty cycle
- tQHmin = tHP-X where
- The previously used definition of tDV(=0.35tCK) artificially penalizes system timing budgets by assuming the worst case
- The JEDEC DDR specification currently defines the output data valid window(tDV) as the time period when the data
COMMAND
. 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
variation and replaces tDV
strobe and all data associated with that data strobe are coincidentally valid.
output valid window even then the clock duty cycle applied to the device is better than 45/55%
CK, CK
DQS
DQ
CS
READA
0
1
1
2
- 14 -
tDQSQ(max)
3
Da0
tQH
tHP
tDQSQ(max)
Da1
4
128M DDR SDRAM
Rev. 1.3 (Jul. 2002)
5