HYB18T512400B2C Datasheet, PDF (50/69 Pages) Qimonda AG – 512-Mbit Double-Data-Rate-Two SDRAM

Internet Data Sheet
HY[B/I]18T512[40/80/16]0B2[C/F](L)
512-Mbit Double-Data-Rate-Two SDRAM
32) When the device is operated with input clock jitter, this parameter needs to be derated by the actual t_JIT.PER of the input clock. (output
deratings are relative to the SDRAM input clock.) For example, if the measured jitter into a DDR2–667 SDRAM has t_JIT.PER.MIN = – 72 ps
and t_JIT.PER.MAX = + 93 ps, then t_{RPRE.MIN(DERATED)} = t_RPRE.MIN + t_JIT.PER.MIN = 0.9 x t_CK.AVG – 72 ps = + 2178 ps and t_{RPRE.MAX(DERATED)} = t_RPRE.MAX
+ t_JIT.PER.MAX = 1.1 x t_CK.AVG + 93 ps = + 2843 ps. (Caution on the MIN/MAX usage!).
33) When the device is operated with input clock jitter, this parameter needs to be derated by the actual t_JIT.DUTY of the input clock. (output
deratings are relative to the SDRAM input clock.) For example, if the measured jitter into a DDR2–667 SDRAM has t_JIT.DUTY.MIN = – 72 ps
and t_JIT.DUTY.MAX = + 93 ps, then t_{RPST.MIN(DERATED)} = t_RPST.MIN + t_JIT.DUTY.MIN = 0.4 x t_CK.AVG – 72 ps = + 928 ps and t_{RPST.MAX(DERATED)} = t_RPST.MAX
+ t_JIT.DUTY.MAX = 0.6 x t_CK.AVG + 93 ps = + 1592 ps. (Caution on the MIN/MAX usage!).
34) For these parameters, the DDR2 SDRAM device is characterized and verified to support t_nPARAM = RU{t_PARAM / t_CK.AVG}, which is in clock
cycles, assuming all input clock jitter specifications are satisfied. For example, the device will support t_nRP = RU{t_RP / t_CK.AVG}, which is in
clock cycles, if all input clock jitter specifications are met. This means: For DDR2–667 5–5–5, of which t_RP = 15 ns, the device will support
t_nRP = RU{t_RP / t_CK.AVG} = 5, i.e. as long as the input clock jitter specifications are met, Precharge command at Tm and Active command at
Tm + 5 is valid even if (Tm + 5 - Tm) is less than 15 ns due to input clock jitter.
35) t_WTR is at lease two clocks (2 x t_CK) independent of operation frequency.
Rev. 1.12, 2007-05
50
10062006-YPTZ-CDR7