DS1086 Spread-Spectrum EconOscillator

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7

Pin Description

PIN

NAME

FUNCTION

1

OUT

Oscillator Output

2

SPRD

Dither Enable. When the pin is high, the dither is enabled. When the pin is low, the dither is disabled.

Power Supply

4

GND

Ground

5OE

Output Enable. When the pin is high, the output buffer is enabled. When the pin is low, the output is

disabled but the master oscillator is still on.

6

PDN

Power-Down. When the pin is high, the master oscillator is enabled. When the pin is low, the master

oscillator is disabled (power-down mode).

7

SDA

2-Wire Serial Data. This pin is for serial data transfer to and from the device. The pin is open drain

and can be wire-OR’ed with other open-drain or open-collector interfaces.

8

SCL

2-Wire Serial Clock. This pin is used to clock data into the device on rising edges and clock data out

on falling edges.

DS1086

DITHERED 260kHz TO

133MHz OUTPUT

DECOUPLING CAPACITORS

(0.1

µF and 0.01µF)

SPRD

OUT

4.7k

Ω

4.7k

Ω

2-WIRE

INTERFACE

GND

SCL

SDA

PDN

OE

Processor-Controlled Mode

DS1086

XTL1/OSC1

MICRO-

PROCESSOR

XTL2/OSC2

DITHERED 260kHz TO

133MHz OUTPUT

DECOUPLING CAPACITORS

(0.1

µF and 0.01µF)

*SDA AND SCL CAN BE CONNECTED DIRECTLY HIGH IF THE DS1086 NEVER NEEDS

TO BE PROGRAMMED IN-CIRCUIT, INCLUDING DURING PRODUCTION TESTING.

SPRD

OUT

GND

N.C.

SCL*

SDA*

PDN

OE

Stand-Alone Mode

CLOCK SPECTRUM COMPARISON

(9kHz BW, PEAK DETECT)

FREQUENCY (MHz)

94

91

93

92

-35

-30

-25

-20

-15

-10

-5

0

-40

90

95

DS1086 NO DITHER

DS1086 4% DITHER

CRYSTAL OSC

Figure 1. Clock Spectrum Dither Comparison

MAXIMUM TEMPERATURE VARIATION

vs. MASTER FREQUENCY

FREQUENCY (MHz)

82.75

116.25

99.50

-1.5

-1.0

-0.5

0

0.5

1.0

1.5

2.0

-2.0

66.00

133.00

Figure 2. Temperature Variation Over Frequency