The following equations provide the PLL
frequency relationships required to achieve closed-loop operation according to the selected
PLL mode. The TICS Pro programming software can be used to generate valid divider settings
based on the desired frequency plan configuration and PLL mode.
- To operate APLL1 in Free-run mode (locked to the XO input), the
conditions in Equation 1 and Equation 2 must be met.
- To operate APLL1 in DPLL mode, the conditions in Equation 1, Equation 2, Equation 3, and Equation 4 must be met.
- To operate APLL2 in Cascaded mode, the conditions in Equation 1, Equation 2, Equation 5, and Equation 7 must be met.
- To operate APLL2 in Non-cascaded mode, the conditions in Equation 6 and Equation 7 must be met.
Note that any divider in the following
equations refer to the actual divide value (or range) and not the programmable register
value.
Equation 1 and Equation 2 relate to
APLL1:
Equation 1. fPD1 =
fXO × DXO / RXO
where
- fPD1 = APLL1 phase detector frequency
- fXO: XO input frequency
- DXO: XO input doubler (1 =
disabled, 2 = enabled)
- RXO: APLL1 XO Input R divider
value (1 to 32)
Equation 2. fVCO1 = fPD1
× (INTAPLL1 + NUMAPLL1 / DENAPLL1)
where
- fVCO1: VCO1 frequency
- INTAPLL1: APLL1 N divider
integer value (12 bits, 1 to 212 – 1)
- NUMAPLL1: APLL1 N divider
numerator value (40 bits, 0 to 240 – 1)
- DENAPLL1: APLL1 N divider
denominator value (fixed 240 or programmable 1 to 224-1)
- 0.0625 < NUMAPLL1 / DENAPLL1 < 0.9375
(In DPLL Mode)
Equation 3 and Equation 4 relate to the
DPLL:
Equation 3. fTDC =
fPRIREF / RPRIREF = fSECREF /
RSECREF
where
- fTDC: DPLL TDC input frequency (see Equation 3)
- fPRIREF or fSECREF:
PRIREF or SECREF input frequency
- RPRIREF or RSECREF:
PRIREF or SECREF R divider value (16 bits, 1 to 216 – 1)
Equation 4. fVCO1 = fTDC
× 2 × PRDPLL × (INTDPLL + NUMDPLL/
DENDPLL)
where
- PRDPLL: DPLL prescaler divider
value (2 to 17)
- INTDPLL: DPLL FB divider
integer value (30 bits, 1 to 230 – 1)
- NUMDPLL: DPLL FB divider
numerator value (40 bits, 0 to 240 – 1)
- DENDPLL: DPLL FB divider
denominator value (40 bits, 1 to 240)
Equation 5, Equation 6, and Equation 7 relate to
APLL2:
Equation 5. Cascaded APLL2:
fPD2 = fVCO1 / (RAPLL2_PRE ×
RAPLL2_SEC)
where
- fPD2: APLL2 phase detector
frequency
- RAPLL2_PRE: Cascaded APLL2 Pre
R divider value (3 to 6)
- RAPLL2_SEC: Cascaded APLL2 Secondary R divider value (1 to
32)
Equation 6. Non-Cascaded APLL2:
fPD2 = fXO × DXO
Equation 7. fVCO2 = fPD2 ×
(INTAPLL2 + NUMAPLL2 / DENAPLL2)
where
- fVCO2: VCO2 frequency
- INTAPLL2: APLL2 N divider integer value (9 bits, 1 to
29 – 1)
- NUMAPLL2: APLL2 N divider
numerator value (24 bits, 0 to 224 – 1)
- DENAPLL2: APLL2 N divider
denominator value (fixed 224 or programmable 1 to 224-1.)
7, Equation 9, Equation 10, and Equation 11 relate to the
output frequency, which depends on the selected APLL clock source and output divider
value:
Equation 8. APLL1 selected:
fCHxMUX = fVCO1
Equation 9. APLL2 selected: fCHxMUX = fVCO2 /
PnAPLL2
Equation 10. OUT[0:6]: fOUTx =
fCHxMUX / ODOUTx
Equation 11. OUT7: fOUT7 = fCH7MUX / (ODOUT7
× OD2)
where
- fCHxMUX: Output mux source
frequency (APLL1 or APLL2 post-divider clock)
- PnAPLL2: APLL2 primary "P1" or
secondary "P2" post-divide value (2 to 7)
- fOUTx: Output clock frequency (x = 0 to 7)
- ODOUTx: OUTx output divider
value (8 bits, 1 to 28)
- OD2: OUT7 secondary output divider value (24 bits, 1 to 224)
- If OD2 > 1, then ODOUT7 ≥ 6