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No nr nf 1 – Rainbow Electronics W90N740 User Manual

Page 36

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W90N740

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INDV [4:0] PLL input clock divider

Input Divider divides the input reference clock into the PLL.

Input Divider

(NR)

PFD

Feedback

Divider

(NF)

Charge

Pump

VCO

Output

Divider

(NO)

Clock

Divider

&

Selector

EXTAL

ECLKS

OTDV[1:0]

CLKS[2:0]

1

0

PLL

Internal

System

Clock

INDV[4:0]

FBDV[8:0]

48MHz

Gen

480MHz

0

1

USBCKS

USB

Module

FIN

FOUT

GP12

Fig 7.2.6 System PLL block diagram

The formula of output clock of PLL is:

F

OUT

= F

IN

NO

NR

NF

1

F

OUT:

Output clock of Output Divider

F

IN:

External clock into the Input Divider

NR:Input divider value (NR = INDV + 2)

NF:Feedback divider value (NF = FBDV + 2)

NO:Output divider value (NO = OTDV)