FS8108

Page 3

Jan 2003

Pin Descriptions

Block Diagram

Number

Name

I/O

Description

1XIN

I

Reference crystal oscillator or external clock input with internally biased amplifier

(any external input to XIN must be ac-coupled)

2

XOUT

O

Reference crystal oscillator or external clock output

3

VDD2

POWER

Nominal 3.0 V supply voltage

4

DB

O

Single-ended quick-lock output for faster locking

5

DO

O

Single-ended charge pump output for passive low pass filter

6

VSS

GND

Ground

7FIN

I

VCO frequency input with internally biased input amplifier

(any external input to FIN must be ac-coupled)

8

VDD1

POWER

Nominal 1.0 V supply voltage

9

NC

NC

No connection

10

LD

O

Lock detector output (high when PLL is locked)

11

CLK

I

Shift register clock input

12

DATA

I

Serial data input

13

LE

I

Latch enable input

14

OPR

I

Battery-save control input; normal operation when high, stand-by mode when low

15

NC

NC

No connection

16

TEST

I

Test mode control input with internal pull-down resistor

PFD

CHARGE

PUMP

FIN

DATA

CLK

LE

TEST

XIN

CONTROL

LOGIC

N-COUNTER

R-COUNTER

SHIFT REGISTER

N-LATCH

R-LATCH

÷ 8

÷ 64/65

LD

DO

XOUT

LOCK

DETECTOR

QUICK-

DB

WINDOW

GENERATOR

OPR

LOCK