Electrical Specifications
9.6.6.2
SDRAM DDR2 400 MHz Clock Specifications
Table 44: SDRAM DDR2 400 MHz Clock Specifications
Description
Clock period jitter
Symbol
tJIT(per)
Min
-100
-80
Max
100
80
Units
ps
ps
ps
ps
ps
ps
ps
ps
ps
ps
ps
ps
ps
ps
Notes
1
2
3
4
5
5
5
5
5
5
6
7
8
9
Clock perior jitter during DLL locking period
Cycle to cycle clock period jitter
tJIT(per,lck)
tJIT(cc)
-200
-160
-150
-175
-200
-200
-300
-450
-100
200
160
150
175
200
200
300
450
100
Cycle to cycle clock period jitter during DLL locking period
Cumulative error across 2 cycles
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
Duty cycle jitter
tJIT(cc,lck)
tERR(2per)
tERR(3per)
tERR(4per)
tERR(5per)
tERR(6-10per)
tERR(11-50per)
tJIT(duty)
Absolute clock period
tCK(abs)
See note 7
Absolute clock high pulse w idth
tCH(abs)
See note 8
See note 9
Absolute clock low pulse w idth
tCL(abs)
Notes :
General comment: All timing values are defined on CLK / CLKn crossing point, unless otherw ise specified.
1. tJIT(per) is defined as the largest deviation of any single tCK from tCK(avg).
tJIT(per) = Min/max of {tCKi- tCK(avg) w here i=1 to 200}.
tJIT(per) defines the single period jitter w hen the DLL is already locked.
2. tJIT(per,lck) uses the same definition for single period jitter, during the DLL locking period only.
3. tJIT(cc) is defined as the difference in clock period betw een tw o consecutive clock cycles: tJIT(cc) = Max of |tCKi+1 – tCKi|.
tJIT(cc) defines the cycle to cycle jitter w hen the DLL is already locked.
4. tJIT(cc,lck) uses the same definition for cycle to cycle jitter, during the DLL locking period only.
5. tERR(nper) is defined as the cumulative error across multiple consecutive cycles fromtCK(avg).
Refer to JEDEC Standard No. 79-2 (DDR2 SDRAM Specification) for more information.
6. tJIT(duty) is defined as the cumulative set of tCH jitter and tCL jitter. tCH jitter is the largest deviation of
any single tCH from tCH(avg). tCL jitter is the largest deviation of any single tCL from tCL(avg).
tJIT(duty) = Min/max of {tJIT(CH), tJIT(CL)} w here,
tJIT(CH) = {tCHi- tCH(avg) w here i=1 to 200}; tJIT(CL) = {tCLi- tCL(avg) w here i=1 to 200}.
7. tCK(abs),min = tCK(avg),min + tJIT(per),min; tCK(abs),max = tCK(avg),max + tJIT(per),max.
8. tCH(abs),min = tCH(avg),min x tCK(avg),min + tJIT(duty),min; tCH(abs),max = tCH(avg),max x tCK(avg),max + tJIT(duty),max.
9. tCL(abs),min = tCL(avg),min x tCK(avg),min + tJIT(duty),min; tCL(abs),max = tCL(avg),max x tCK(avg),max + tJIT(duty),max.
Copyright © 2008 Marvell
MV-S104671-U0 Rev. C
Page 87
December 6, 2008, Preliminary
Document Classification: Proprietary Information
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