Loop Filter For Vco Pll - Renesas 8V19N49 Series Manual

8V19N49x Hardware Design Guide
R3
C3
1. Other VCXO frequencies can also be used with proper loop filter and parameter setting. Below are examples of VCXO order information:
* 122.88MHz - Epson VG3225EFN 122.88M-CJHHBA
* 245.76MHz - Epson VG3225ENN 245.76M-CJHHMA
* 491.52MHz - Epson VG3225ENN 491.52M-CJGHSA
3.3.2

Loop Filter for VCO PLL

The 8V19N490 VCO phase lock loop diagram is displayed in
this example, the 2949.12MHz VCO is used. A 2
The board-level VCO 2nd order loop filter works in conjunction with the internal circuitries. A traditional loop filter
calculation method may not be accurate. After simulation and actual experiment, an example of external two-pole
loop filter value is provided in
R31UH0005EU0100 Rev.1.0
Jun 3, 2021
Table 2. Loop Filter Examples (Cont.)
51k Ohm
nd
order loop filter for the VCO is shown in
Figure 11. VCO PLL Block Diagram
Rz
Cz
nd
Figure 12. 2 Order Loop Filter for the VCO
Table 3.
4.7nF
Figure 11. The Fvco frequency is 2.94912GHz. In
LFF
Cp
LFFR
1.8k Ohm
33nF
Figure 12.
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