CY25245OXC Cypress Semiconductor Corp, CY25245OXC Datasheet - Page 4

• Manufacturer Part Number: CY25245OXC
• Manufacturer: Cypress Semiconductor Corp

Specifications of CY25245OXC

• Lead Free Status / RoHS Status: Compliant

Document #: 38-07124 Rev. *B
Spread Spectrum Frequency Timing Generator
The device generates a clock that is frequency modulated in
order to increase the bandwidth that it occupies. By increasing
the bandwidth of the fundamental and its harmonics, the ampli-
tudes of the radiated electromagnetic emissions are reduced.
This effect is depicted in Figure 2.
As shown in Figure 2, a harmonic of a modulated clock has a
much lower amplitude than that of an unmodulated signal. The
reduction in amplitude is dependent on the harmonic number
and the frequency deviation or spread.
MAX.
MIN.
Figure 2. Clock Harmonic with and without SSCG Modulation Frequency Domain Representation
Figure 3. Typical Modulation Profile
The output clock is modulated with a waveform depicted in
Figure 3. This waveform, as discussed in “Spread Spectrum
Clock Generation for the Reduction of Radiated Emissions” by
Bush, Fessler, and Hardin, produces the maximum reduction
in the amplitude of radiated electromagnetic emissions. The
deviation selected for this chip is as described in Table 2.
Figure 3 details the Cypress spreading pattern. Cypress does
offer options with more spread and greater EMI reduction.
Contact your local Sales representative for details on these
devices.
Spectrum
Enabled
Spread
EMI Reduction
Frequency Span (MHz)
Down Spread
CY25245
Spread
Spectrum
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