EtronTech
EM68C16CWQG
Table 30. Input clock jitter spec parameter
-18I
-25I
-3I
Parameter
Clock period jitter
Symbol
Unit Note
Min. Max. Min. Max. Min. Max.
tJIT (per)
tJIT (per,lck)
tJIT (cc)
-90
-80
90 -100 100 -125 125
80 -80 80 -100 100
ps
ps
ps
ps
ps
ps
ps
ps
ps
ps
ps
33
33
33
33
33
33
33
33
33
33
33
Clock period jitter during DLL locking
period
Cycle to cycle clock period jitter
-180 180 -200 200 -250 250
-160 160 -160 160 -200 200
-132 132 -150 150 -175 175
-157 157 -175 175 -225 225
-175 175 -200 200 -250 250
-188 188 -200 200 -250 250
Cycle to cycle clock period jitter during DLL
locking period
Cumulative error across 2 cycles
tJIT (cc,lck)
tERR (2per)
tERR (3per)
tERR (4per)
tERR (5per)
Cumulative error across 3 cycles
Cumulative error across 4 cycles
Cumulative error across 5 cycles
Cumulative error across n cycles, n=6...10,
inclusive
Cumulative error across n cycles,
n=11...50, inclusive
tERR (6-10per) -250 250 -300 300 -350 350
tERR (11-50per) -425 425 -450 450 -450 450
Duty cycle jitter
tJIT (duty)
-75
75 -100 100 -125 125
NOTE 34: These parameters are specified per their average values, however it is understood that the following
relationship between the average timing and the absolute instantaneous timing holds at all times. (Min
andmax of SPEC values are to be used for calculations in the table below.)
Table 31. Absolute clock period average values
Parameter
Symbol
Min.
Max.
Unit
Absolute clock period
tCK (abs)
tCK(avg),min + tJIT(per),min
tCK(avg),max + tJIT(per),max
ps
Absolute clock HIGH pulse width
Absolute clock LOW pulse width
tCH (abs)
tCL (abs)
tCH(avg),min * tCK(avg),min + tCH(avg),max * tCK(avg),max + ps
tJIT(duty),min tJIT(duty),max
tCL(avg),min * tCK(avg),min + tCL(avg), max * tCK(avg),max + ps
tJIT(duty),min tJIT(duty), max
NOTE 35: tHP is the minimum of the absolute half period of the actual input clock. tHP is an input parameter but not
an input specification parameter. It is used in conjunction with tQHS to derive the DRAM output timing tQH
The value to be used for tQH calculation is determined by the following equation;
.
tHP = Min ( tCH(abs), tCL(abs) ),
where,
tCH(abs) is the minimum of the actual instantaneous clock HIGH time;
tCL(abs) is the minimum of the actual instantaneous clock LOW time;
NOTE 36: tQHS accounts for:
1) The pulse duration distortion of on-chip clock circuits, which represents how well the actual tHP at the
input is transferred to the output; and
2) The worst case push-out of DQS on one transition followed by the worst case pull-in of DQ on the next
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.}
Rev. 1.2
32
Apr. /2016
ETRON [ ETRON TECHNOLOGY, INC. ]
