The APLL phase locks the APLL VCO to
the APLL reference using the applied APLL numerator and is calculated using Equation 2.
Equation 2. fVCO =
fPD × (INTAPLL + NUMAPLL /
DENAPLL)
- fVCO: VCO
frequency
- INTAPLL: APLL N
divider integer value (12 bits, 1 to 212 – 1)
- NUMAPLL: APLL N
divider numerator value (40 bits, 0 to 240 – 1, or 24 bits, 0 to
224 – 1 )
- DENAPLL: APLL N
divider denominator value (fixed 240, or programmable 1 to
224)
- Avoid integer boundary
spurs by keeping the NUM/DEN ratio away from an integer value.
- 0.125 < NUMAPLL / DENAPLL <
0.875 (In DPLL Mode, avoid 0.5)