K4H561638N-LCB3T00 Datasheet, PDF (19/24 Pages) Samsung semiconductor – N-die DDR SDRAM

K4H560438N
K4H560838N
K4H561638N
datasheet
Rev. 1.01
DDR SDRAM
20. Min (tCL, tCH) refers to the smaller of the actual clock low time and the actual clock high time as provided to the device (i.e. this value can be greater
than the minimum specification limits for tCL and tCH).....For example, tCL and tCH are = 50% of the period, less the half period jitter (tJIT(HP)) of
the clock source, and less the half period jitter due to crosstalk (tJIT(crosstalk)) into the clock traces.
21. tQH = tHP - tQHS, where:
tHP = minimum half clock period for any given cycle and is defined by clock high or clock low (tCH, tCL). tQHS accounts for 1) The pulse duration dis-
tortion of on-chip clock circuits; and 2) The worst case push-out of DQS on one tansition followed by the worst case pull-in of DQ on the next transi-
tion, both of which are, separately, due to data pin skew and output pattern effects, and p-channel to n-channel variation of the output drivers.
22. tDQSQ
Consists of data pin skew and output pattern effects, and p-channel to n-channel variation of the output drivers for any given cycle.
23. tDAL = (tWR/tCK) + (tRP/tCK)
For each of the terms above, if not already an integer, round to the next highest integer. Example: For DDR400 at CL=3 and tCK=5ns tDAL = (15 ns /
5 ns) + (15 ns/ 5ns) = (3) + (3) tDAL = 6 clocks
- 19 -