EDJ1108BABG, EDJ1116BABG
26. For these parameters, the DDR3 SDRAM device is characterized and verified to support
tnPARAM [nCK] = RU{tPARAM [ns] / tCK(avg)}, which is in clock cycles, assuming all input clock jitter
specifications are satisfied.
For example, the device will support tnRP = RU{tRP / tCK(avg)}, which is in clock cycles, if all input clock
jitter specifications are met. This means: For DDR3-800 6-6-6, of which tRP = 15ns, the device will
support tnRP =RU{tRP / tCK(avg)} = 6, i.e. as long as the input clock jitter specifications are met,
precharge command at Tm and active command at Tm+6 is valid even if (Tm+6 − Tm) is less than 15ns
due to input clock jitter.
27. These parameters should be the larger of the two values, analog (ns) and number of clocks (nCK).
28 The tRAS lockout circuit internally delays the Precharge operation until the array restore operation has
been completed so that the auto precharge command may be issued with any read or write command.
29 Defined between end of MPR read burst and MRS which reloads MPR or disables.
30 One ZQCS command can effectively correct a minimum of 0.5% (ZQCorrection) of RON and RTT
impedance error within 64nCK 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:
×
×
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:
×
×
31 The tIS(base) AC150 specifications are adjusted from the tIS(base) specification by adding an additional
100ps of derating to accommodate for the lower alternate threshold of 150mV and another 25ps to
account for the earlier reference point [(175mV − 150mV)/1V/ns].
32 Pulse width of a input signal is defined as the width between the first crossing of VREF(DC) and the
consecutive crossing of VREF(DC).
33 tDQSL describes the instantaneous differential input low pulse width on DQS − /DQS, as measured from
one falling edge to the next consecutive rising edge.
34 tDQSH describes the instantaneous differential input high pulse width on DQS −/DQS, as measured from
one rising edge to the next consecutive falling edge.
35 tDQSH,act + tDQSL,act = 1tCK,act ; with tXYZ,act being the actual measured value of the respective
timing parameter in the application.
36 tDSH,act + tDSS,act = 1tCK,act ; with tXYZ,act being the actual measured value of the respective timing
parameter in the application.
37 When the device is operated with input clock jitter, this parameter needs to be derated by the actual
tERR(mper),act of the input clock, where 2 ≤ m ≤ 12. (output deratings are relative to the SDRAM input
clock.)
For example, if the measured jitter into a DDR3-800 SDRAM has tERR(mper),act,min = −172ps and
tERR(mper),act,max = +193ps, then tDQSCK,min(derated) = tDQSCK,min − tERR(mper),act,max =
−400ps − 193ps = −593ps and tDQSCK,max(derated) =tDQSCK,max − tERR(mper),act,min = 400ps +
172ps = +572ps. Similarly, tLZ(DQ) forDDR3-800 derates to tLZ(DQ),min(derated) = −800ps − 193ps =
−993ps and tLZ(DQ),max(derated) = 400ps + 172ps = +572ps. Note that tERR(mper),act,min is the
minimum measured value of tERR(nper) where 2 ≤ n ≤ 12, and tERR(mper),act,max is the maximum
measured value of tERR(nper) where 2 ≤ n ≤ 12.
38 When the device is operated with input clock jitter, this parameter needs to be derated by the actual
tJIT(per),act of the input clock. (output deratings are relative to the SDRAM input clock.)
For example, if the measured jitter into a DDR3-800 SDRAM has tCK(avg),act = 2500ps, tJIT(per),act,min
= − 72ps and tJIT(per),act,max = +93ps, then tRPRE,min(derated) = tRPRE,min + tJIT(per),act,min = 0.9
× tCK(avg),act + tJIT(per),act,min = 0.9 × 2500ps − 72ps = +2178ps. Similarly, tQH,min(derated) =
tQH,min + tJIT(per),act,min = 0.38 × tCK(avg),act + tJIT(per),act,min = 0.38 × 2500ps − 72ps = + 878ps.
Data Sheet E1248E40 (Ver. 4.0)
59
ELPIDA [ ELPIDA MEMORY ]
