Renesas 9FGV100 Series User Manual page 13

Example 1 with Down Spread :
F =2500MHz, F =100MHz with -0.5% Down Spread and 31.5KHz Modulation Rate.
VCO CLOCK
At 100MHz the JA Multiplier is 1 so F
FOD value P = (1 + SS% / 100) × (F
FOD Integer [7..0] = DEC2HEX(12) = 0C-hex
FOD Fraction [15..0] = DEC2HEX(ROUND2INT(216×0.5625)) = DEC2HEX(ROUND2INT(36864)) = 90 00 hex
Period (decimal) = FOUT / (2×F
Period [11:0] = DEC2HEX(ROUND2INT(Period(decimal) / 2)) = DEC2HEX(794) = 3 1A hex
Step (decimal) = (SS% / 100) × P / Period = (0.5 / 100) × 12.5625 / 1587.3016 = 3.95719 × 10
Step [15..0] = DEC2HEX(ROUND2INT(2
Example 2 with Center Spread :
F =2500MHz, F =27MHz with +/-1.0% Center Spread and 31.5KHz Modulation Rate.
VCO OUT
At 27MHz the JA Multiplier is 0.25 so F
FOD value P = (1 + SS% / 200) × (F
FOD Integer [7..0] = DEC2HEX(11) = 0B-hex
FOD Fraction [15..0] = DEC2HEX(ROUND2INT(2
Period (decimal) = FOUT / (2×F
Period [11:0] = DEC2HEX(ROUND2INT(Period(decimal) / 2)) = DEC2HEX(857) = 3 59 hex
Step (decimal) = (SS% / 100) × P / Period = (2.0 / 100) × 11.689815 / 1714.2857 = 1.363812 × 10
Step [15..0] = DEC2HEX(ROUND2INT(2
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= F and the JA setting is JA[1..0] = 01 binary.
OUT CLOCK
/ (2 × F )) = (1 + 0.5/100) × (2500 / (2×100)) = 1.005 × 12.5 = 12.5625
VCO OUT
) = 100 / (2×0.0315) = 1587.3016
SS
24
× Step(decimal))) = DEC2HEX(664) = 02 98 hex
= 4×F = 108MHz and the JA setting is JA[1..0] = 00 binary.
OUT CLOCK
/ (2 × F )) = (1 + 2.0/200) × (2500 / (2×108)) = 1.01 × 11.574074 = 11.689815
VCO OUT
16
×0.689815)) = DEC2HEX(ROUND2INT(45207.7)) = B0 98 hex
) = 108 / (2×0.0315) = 1714.2857
SS
24
× Step(decimal))) = DEC2HEX(2288) = 08 F0 hex
9FGV100x Register Descriptions and Programming Guide User Guide
13
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November 18, 2016