5L35021 Ver la hoja de datos (PDF) - Integrated Device Technology
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5L35021 Datasheet PDF : 37 Pages
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5L35021 Datasheet
XTAL[4:0] = (XTAL CL - 7pF) *2 (Eq.1)
Equation 1 and the table of XTAL[7:0] tuning capacitor characteristics show that the parallel tuning capacitance can be set between 4.5pF
to 12.5pF with a resolution of 0.25pF.
For a crystal CL = 8pF, where CL is the parallel capacity specified by the crystal vendor that sets the crystal frequency to the nominal
value. Under the assumptions that the stray capacity between the crystal leads on the circuit board is zero and that no external tuning
caps are placed on the crystal leads, then the internal parallel tuning capacity is equal to the load capacity presented to the crystal by the
device.
The internal load capacitors are true parallel-plate capacitors for ultra-linear performance. Parallel-plate capacitors were chosen to
reduce the frequency shift that occurs when non-linear load capacitance interacts with load, bias, supply, and temperature changes.
External non-linear crystal load capacitors should not be used for applications that are sensitive to absolute frequency requirements.
The 5L35023 supports spread spectrum clocks from PLL1 and PLL2; the PLL1 built-in with analog spread spectrum and PLL2 has digital
spread spectrum.
Spread Spectrum
The 5L35021 supports spread spectrum clocks from PLL1 and PLL2; the PLL1 built-in with analog spread spectrum and PLL2 has digital
spread spectrum.
Table 25. Spread Spectrum Generation Specifications
Symbol
fOUT
fMOD
fSPREAD
Parameter
Output Frequency
Mod Frequency
Spread Value
%tolerance Spread% Value
Description
Output frequency range.
Modulation frequency.
Amount of spread value
(programmable) – down spread.
Variation of spread range.
Minimum
Typical
1
30 to 63
-0.5% to -2%
Maximum
125
Units
MHz
kHz
% fOUT
15
%
©2017 Integrated Device Technology, Inc.
17
July 13, 2017
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