DS1086 Datasheet, PDF (7/14 Pages) Dallas Semiconductor – DS1086 Spread-Spectrum EconOscillator

DS1086 Spread-Spectrum EconOscillator
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.
3
V_CC
Power Supply
4
GND
Ground
5
OE
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.
CLOCK SPECTRUM COMPARISON
(9kHz BW, PEAK DETECT)
0
CRYSTAL OSC
-5
DS1086 NO DITHER
-10
-15
DS1086 4% DITHER
-20
-25
-30
-35
-40
90
91
92
93
94
95
FREQUENCY (MHz)
Figure 1. Clock Spectrum Dither Comparison
Processor-Controlled Mode
V_CC
DITHERED 260kHz TO
133MHz OUTPUT
V_CC ^OUT
SPRD
V_CC
GND
DS1086
DECOUPLING CAPACITORS
(0.1µF and 0.01µF)
4.7kΩ
SCL
SDA
V_CC
PDN
OE
4.7kΩ
2-WIRE
INTERFACE
MAXIMUM TEMPERATURE VARIATION
vs. MASTER FREQUENCY
2.0
1.5
1.0
0.5
0
-0.5
-1.0
-1.5
-2.0
66.00
82.75 99.50 116.25
FREQUENCY (MHz)
133.00
Figure 2. Temperature Variation Over Frequency
Stand-Alone Mode
MICRO-
PROCESSOR
DITHERED 260kHz TO
133MHz OUTPUT
V_CC
XTL1/OSC1
V_CC ^OUT
SCL*
XTL2/OSC2 N.C.
SPRD _DS1086 SDA*
V_CC
PDN
GND
OE
DECOUPLING CAPACITORS
(0.1µF 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.
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