FS781/82/84

Table 2. FS781/82/84 Recommended Loop Filter Values C7 (pF) @ +3.3 VDC ±5% (R6 = 3.3K)[1, 2, 3, 4]
Input MHz	S1	S0	BW = 1.0%[3]	BW = 1.5%[3]	BW = 2.0%[3]	BW = 2.5%[3]	BW = 3.0%[3]	BW = 3.5%[3]	BW = 4.0%[3]
6	0	0	10,000/1000	1550	910	780	700	640	560

8	0	0	10,000/330	990	820	640	520	450	400

10	0	0	1040	680	460	360	300	240	210

12	0	0	830	420	300	220	200	190	170

14	0	0	580	230	200	160	140	100	80

16	0	1	10000	980	760	580	470	410	385

18	0	1	1200	750	580	470	415	370	300

20	0	1	1000	730	470	390	320	220	190

22	0	1	960	640	410	270	230	200	180

24	0	1	920	400	250	210	180	160	150

26	0	1	660	300	220	180	150	140	120

28	0	1	470	230	180	150	130	100	70

30	0	1	470	180	140	120	100	80	60

32	0	1	330	170	120	100	82	68	47

34	1	0	10000	860	640	520	430	380	330

36	1	0	2200	820	620	470	400	330	290

38	1	0	1500	690	520	410	340	290	240

40	1	0	960	600	420	340	280	220	160

42	1	0	940	620	380	275	230	210	180

44	1	0	950	680	400	250	210	190	170

46	1	0	900	580	270	220	190	180	165

48	1	0	790	440	260	210	180	160	140

50	1	0	660	360	250	190	170	150	140

52	1	0	470	325	220	185	155	135	120

54	1	0	470	270	200	170	140	130	100

56	1	0	445	250	185	150	120	85	47

58	1	0	430	210	165	130	100	65	33

60	1	0	295	185	150	120	100	90	82

62	1	0	270	220	150	120	100	82	68

64	1	1	1180	860	560	410	340	290	230

65	1	1	1180	850	540	400	330	280	220

66	1	1	1180	760	560	350	260	220	210

68	1	1	1180	750	500	320	260	230	210

70	1	1	1120	740	470	370	300	240	170

72	1	1	1160	780	470	300	250	220	190

74	1	1	1110	770	470	280	230	210	190

76	1	1	1000	720	440	240	210	190	170

78	1	1	910	670	270	210	190	170	160

80	1	1	900	620	260	210	190	170	156

82	1	1	900	540	250	210	190	170	150

Notes:

1.If the value selected from the above chart is not a standard, use the next available larger value.

2.All bandwidths indicated above are total peak-to-peak spread. 1% = +0.5% to –0.5%. 4% = +2.0% to –2.0%.

3.If C8 is not listed in the chart for a particular bandwidth and frequency, it is not used in the loop filter.

4.Contact Cypress for LF values less than 1.0% bandwidth.

Document #: 38-07029 Rev. *F

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