AS4C64M8D2 datasheet(32/59 Pages) ALSC

32 / 59 page

AS4C64M8D2

Confidential

Rev. 1.0

Feb. /2014

transition, both of which are independent of each other, due to data pin skew, output pattern effects, and p-

channel to n-channel variation of the output drivers

NOTE 37: tQH = tHP – tQHS, where: tHP is the minimum of the absolute half period of the actual input clock; and tQHS is

the specification value under the max column. {The less half-pulse width distortion present, the larger the tQH

value is; and the larger the valid data eye will be.}

NOTE 38: When the device is operated with input clock jitter, this parameter needs to be derated by the actual

tERR(6-10per) of the input clock. (output deratings are relative to the SDRAM input clock.)

NOTE 39: When the device is operated with input clock jitter, this parameter needs to be derated by the actual

tJIT(per) of the input clock. (output deratings are relative to the SDRAM input clock.)

NOTE 40: When the device is operated with input clock jitter, this parameter needs to be derated by the actual

tJIT(duty) of the input clock. (output deratings are relative to the SDRAM input clock.)

NOTE 41: When the device is operated with input clock jitter, this parameter needs to be derated by { -

tJIT(duty),max - tERR(6-10per),max } and { - tJIT(duty),min - tERR(6-10per),min } of the actual input clock. (output

deratings are relative to the SDRAM input clock.)

NOTE 42: For tAOFD of DDR2-667/800, the 1/2 clock of tCK in the 2.5 x tCK assumes a tCH(avg), average input clock

HIGH pulse width of 0.5 relative to tCK(avg). tAOF,min and tAOF,max should each be derated by the same

amount as the actual amount of tCH(avg) offset present at the DRAM input with respect to 0.5.

NOTE 43: If refresh timing is violated, data corruption may occur and the data must be re-written with valid data

before a valid READ can be executed.

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