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Crystal

Oscillator

Feedback

Divider

Output

Divider

PFD/

ChargePump

Prescaler

LoopFilter

XIN1

XIN2

B0230-01

VCO

PACKAGE (QFN-24)

NC

V

CC

15

14

13

RGEPACKAGE

(TOP VIEW)

CDC421xxx

NC

1

2

3

NC

4

NC

5

NC

18

NC

17

V

CC

16

NC

NC

CE

NC

P0024-06

6

CDC421xxx

SLAS540 – APRIL 2007

Figure 1. High-Level Block Diagram of the CDC421xxx

The CDC421xxx is packaged in a QFN-24 terminal package. The QFN package footprint is shown. Terminal

locations and numbers are shown in Figure 2.

Figure 2. Pinout of the CDC421xxx QFN-24 Package

The terminal functions table shows the terminal descriptions for the CDC421xxx QFN-24 package.

Table 1. TERMINAL FUNCTIONS

TERMINAL

ESD

TYPE

DESCRIPTION

PROTECTION

NAME

NO.

16, 17

Power

Y

3.3V power supply

GND

8, 9

GND

Y

Ground

In crystal input mode, connect XIN1 to one end of the crystal and XIN2 to the

XIN 1

21

I

Y

other end of the crystal. In LVCMOS single-ended driven mode, XIN1 (pin 21) acts

XIN 2

22

I

N

as input reference and XIN2 should connect to GND.

2

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