Spread-Spectrum Crystal Multiplier

CRYSTAL

OSCILLATOR

1x/2x/4x CLOCK MULTIPLYING

PLL WITH SPREAD SPECTRUM

CONFIGURATION DECODE

AND CONTROL

GND

PDN

SSO

CMSEL

SMSEL

X1

X2

16MHz

TO

33.4MHz

TO

134MHz

DS1080L

Block Diagram

Pin Description

PIN

NAME

FUNCTION

1

X1

Crystal Drive/Clock Input. A crystal with the proper loading capacitors is connected across X1 and X2.

Instead of a crystal, a clock can be applied at the X1 input.

2

GND

Signal Ground

3

CMSEL

Clock Multiplier Select. Tri-level digital input.

0 = 1x

Float = 2x

1 = 4x

4

SMSEL

Spread-Spectrum Magnitude Select. Tri-level digital input.

0 = ±0.5%

Float = ±1.0%

1 = ±1.5%

5

PDN

Power-Down/Spread-Spectrum Disable. Tri-level digital input.

0 = Power-Down/SSO Three-Stated

Float = Power-Up/Spread Spectrum Disabled

1 = Power-Up/Spread Spectrum Enabled

6

SSO

Spread-Spectrum Clock Multiplier Output. Outputs a 1x, 2x, or 4x spread-spectrum version of the crystal

or clock applied at the X1/X2 pins.

7

Supply Voltage

8

X2

Crystal Drive Output. A crystal with the proper loading capacitors is connected across X1 and X2.

If a clock is connected to X1, then X2 should be left open circuit.

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