HYB18T512xxxBF–[2.5…5]
512-Mbit Double-Data-Rate-Two SDRAM
11) The tHZ, tRPST and tLZ, tRPRE parameters are referenced to a specific voltage level, which specify when the device output is
no longer driving (tHZ, tRPST), or begins driving (tLZ, tRPRE). tHZ and tLZ transitions occur in the same access time windows as
valid data transitions.These parameters are verified by design and characterization, but not subject to production test.
12) The Auto-Refresh command interval has be reduced to 3.9 µs when operating the DDR2 DRAM in a temperature range
between 85 °C and 95 °C.
13) 0 °C≤ TCASE ≤ 85 °C
14) 85 °C < TCASE ≤ 95 °C
15) A maximum of eight Auto-Refresh commands can be posted to any given DDR2 SDRAM device.
16) tRP(A) for a Precharge-All command for an 8 bank device is equal to tRP + 1tCK, where tRP are the values for a single bank
precharge.
17) The tRRD timing parameter depends on the page size of the DRAM organization. See Chapter 1
18) The maximum limit for the tWPST parameter is not a device limit. The device operates with a greater value for this parameter,
but system performance (bus turnaround) degrades accordingly.
19) WR must be programmed to fulfill the minimum requirement for the tWR timing parameter, where
WRMIN[cycles] = tWR(ns)/tCK(ns) rounded up to the next integer value. tDAL = WR + (tRP/tCK). For each of the terms, if not
already an integer, round to the next highest integer. tCK refers to the application clock period. WR refers to the WR
parameter stored in the MRS.
20) Minimum tWTR is two clocks when operating the DDR2-SDRAM at frequencies ≤ 200 ΜΗz.
21) User can choose two different active power-down modes for additional power saving via MRS address bit A12. In “standard
active power-down mode” (MR, A12 = “0”) a fast power-down exit timing tXARD can be used. In “low active power-down
mode” (MR, A12 =”1”) a slow power-down exit timing tXARDS has to be satisfied.
Internet Data Sheet
49
Rev. 1.05, 2007-01
03292006-YBYM-WG0Z
QIMONDA [ QIMONDA AG ]
