U74HC4046A

CMOS IC

UNISONICTECHNOLOGIESCO.,LTD

15 of 19

www.unisonic.com.tw

QW-R502-461.C

APPLICATION INFORMATION

This is a reference for the values of external components to be used with the U74HC4046A in a PLL system.

The ranges of the values of the components:

VCO Frequency Without Extra Offset

(Phase comparator: PC1, PC2 or PC3)

Frequency Characteristic:

Fig.11 Frequency characteristic of VCO operating without offset:

Component

Value

R1

3 kΩ ~ 300 kΩ

R2

3 kΩ ~ 300 kΩD

R1+R2

Parallel value > 2.7 kΩ

C1

Greater than 40 pF