VR4102 datasheet(683/701 Pages) NEC

683 / 701 page

683

CHAPTER 29 PLL PASSIVE COMPONENTS

The Phase Locked Loop circuit requires several passive components for proper operation, which are connected

to V

DDP and GNDP as illustrated in Figure 29-1.

Figure 29-1. Example of Connection of PLL Passive Components

VDD

VDDP

GNDP

GND

VR4102

Remarks1. C1, C2, C3 capacitors and R resistors are mounted on the printed circuit board.

2. Since the value for the components depends upon the application system, the optimum

values for each system should be decided after repeated experimentation.

It is essential to isolate the analog power and ground for the PLL circuit (V

DDP/GNDP) from the regular power and

ground (V

DD/GND).

Initial evaluations have yielded good results with the following values:

R = 5

C1 = 1 nF

C2 = 2 nF

C3 = 10

Since the optimum values for the filter components depend upon the application and the system noise

environment, these values should be considered as starting points for further experimentation within your specific

application. In addition, the chokes (inductors:

L) can be considered for use as an alternative to the resistors (R) for

use in filtering the power supply.

VR4102 Datasheet(PDF) 683 Page - NEC