2Gb DDR3 SDRAM G-Die
NT5CB512M4GN / NT5CB256M8GN
NT5CC512M4GN / NT5CC256M8GN
121
REV 1.1
08/ 2011
Timing Parameter Notes
1. Actual value dependent upon measurement level definitions which are TBD.
2. Commands requiring a locked DLL are: READ ( and RAP) are synchronous ODT commands.
3. The max values are system dependent.
4. WR as programmed in mode register.
5. Value must be rouned-up to next higher integer value.
6. There is no maximum cycle time limit besides the need to satisfy the refresh interval, tREFI.
7. For definition of RTT-on time tAON See “Timing Parameters”.
8. For definition of RTT-off time tAOF See “Timing Parameters”.
9. tWR is defined in ns, for calculation of tWRPDEN it is necessary to round up tWR / tCK to the next integer.
10. WR in clock cycles are programmed in MR0.
11. The maximum read postamble is bounded by tDQSCK(min) plus tQSH(min) on the left side and tHZ(DQS)max on the
right side.
12. Output timing deratings are relative to the SDRAM input clock. When the device is operated with input clock jitter, this
parameter needs to be derated by TBD.
13. Value is only valid for RON34.
14. Single ended signal parameter.
15. tREFI depends on TOPER.
16. tIS(base) and tIH(base) values are for 1V/ns CMD/ADD single-ended slew rate and 2V/ns CK, CK differential slew
rate. Note for DQ and DM signals, VREF(DC)=VRefDQ(DC). For input only pins except RESET,
VRef(DC)=VRefCA(DC).
17. tDS(base) and tDH(base) values are for 1V/ns DQ single-ended slew rate and 2V/ns DQS, DQS differential slew rate.
Note for DQ and DM signals, VREF(DC)=VRefDQ(DC). For input only pins except RESET, VRef(DC)=VRefCA(DC).
18. Start of internal write transaction is defined as follows:
For BL8 (fixed by MRS and on-the-fly): Rising clock edge 4 clock cycles after WL.
For BC4 (on-the-fly): Rising clock edge 4 clock cycles after WL.
For BC4 (fixed by MRS): Rising clock edge 2 clock cycles after WL.
19. The maximum preamble is bound by tLZ (DQS) max on the left side and tDQSCK(max) on the right side.
20. CKE is allowed to be registered low while operations such as row activation, precharge, autoprecharge or refresh are
in progress, but power-down IDD spec will not be applied until finishing those operations.
21. Although CKE is allowed to be registered LOW after a REFRESH command once tREFPDEN (min) is satisfied, there
are cases where additional time such as tXPDLL (min) is also required.
22. Defined between end of MPR read burst and MRS which reloads MPR or disables MPR function.
23. One ZQCS command can effectively correct a minimum of 0.5% (ZQCorrection) of RON and RTT impedance error
within 64 nCK for all speed bins assuming the maximum sensitivities specified in the “Output Driver Voltage and
Temperature Sensitivity” and “ODT Voltage and Temperature Sensitivity” tables. The appropriate interval between
ZQCS commands can be determined from these tables and other application-specific parameters.
One method for calculating the interval between ZQCS commands, given the temperature (Tdriftrate) and voltage
(Vdriftrate) drift rates that the SDRAM is subject to in the application, is illustrated. the interval could be defined by the
following formula: ZQCorrection / [(TSens x Tdriftrate) + (VSens x Vdriftrate)] where TSens = max(dRTTdT,
dRONdTM) and VSens = max(dRTTdV, dRONdVM) define the SDRAM temperature and voltage sensitivities.
For example, if TSens = 1.5%/C, VSens = 0.15%/mV, Tdriftrate = 1 C/sec and Vdriftrate = 15mV/sec, then the interval
between ZQCS commands is calculated as 0.5 / [(1.5x1)+(0.15x15)] = 0.133 ~ 128ms
24. n = from 13 cycles to 50 cycles. This row defines 38 parameters.
25. tCH(abs) is the absolute instantaneous clock high pulse width, as measured from one rising edge to the following
falling edge.
26. tCL(abs) is the absolute instantaneous clock low pulse width, as measured from one falling edge to the following rising
edge.
27. The tIS(base) AC150 specifications are adjusted from the tIS(base) specification by adding an additional 100ps of
derating to accommodate for the lower altemate threshold of 150mV and another 25ps to account for the earlier
reference point [(175mV - 150mV) / 1V/ns].