Marvel Group 88F6281 Sdram DDR2 Clock Specifications, Description Symbol Min Max Units

88F6281

Hardware Specifications

8.6.2.2SDRAM DDR2 Clock Specifications

Table 48: SDRAM DDR2 Clock Specifications

Description	Symbol	Min	Max	Units	Notes
Clock period jitter	tJIT(per)	-100	100	ps	1
Clock perior jitter during DLL locking period	tJIT(per,lck)	-80	80	ps	2
Cycle to cycle clock period jitter	tJIT(cc)	-200	200	ps	3
Cycle to cycle clock period jitter during DLL locking period	tJIT(cc,lck)	-160	160	ps	4
Cumulative error across 2 cycles	tERR(2per)	-150	150	ps	5
Cumulative error across 3 cycles	tERR(3per)	-175	175	ps	5
Cumulative error across 4 cycles	tERR(4per)	-200	200	ps	5
Cumulative error across 5 cycles	tERR(5per)	-200	200	ps	5
Cumulative error across n cycles, n=6...10, inclusive	tERR(6-10per)	-300	300	ps	5
Cumulative error across n cycles, n=11…50, inclusive	tERR(11-50per)	-450	450	ps	5
Duty cycle jitter	tJIT(duty)	-100	100	ps	6
Absolute clock period	tCK(abs)	See note 7		ps	7
Absolute clock high pulse w idth	tCH(abs)	See note 8		ps	8
Absolute clock low pulse w idth	tCL(abs)	See note 9		ps	9

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 is defined as the cumulative error across multiple consecutive cycles from tCK(avg).

Please refer to JEDEC Standard No. 79-2C (DDR2 SDRAM Specification), Chapter 5 (page 100) 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.

Doc. No. MV-S104859-U0 Rev. E		Copyright © 2008 Marvell
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