Clock Generator (SSCG) ICs used for the purpose of reducing
EMI found in today’s high-speed digital electronic systems.
The devices use a Cypress proprietary phase-locked loop
(PLL) and Spread Spectrum Clock (SSC) technology to
synthesize and modulate the frequency of the input clock. By
frequency modulating the clock, the measured EMI at the
fundamental and harmonic frequencies is greatly reduced.
This reduction in radiated energy can significantly reduce the
cost of complying with regulatory agency requirements and
improve time to market without degrading system performance.
The input frequency range is 8–16 MHz for the CY25818 and
16–32 MHz for the CY25819. Both products accept external
clock, crystal, or ceramic resonator inputs.
The CY25818/19 provide separate modulated (SSCLK) and
unmodulated reference (REFCLK) clock outputs which are the
same frequency as the input clock frequency. Down spread
frequency modulation can be selected by the user, based on
three discrete values of Spread%. A separate power down
function is also provided.
The CY25818/19 products are available in an 8-pin SOIC
(150-mil) package with a commercial operating temperature
range of 0–70°C. Contact Cypress for availability of –40 to
+85°C industrial temperature range operation or TSSOP
package versions. Refer to the CY25568, CY25811,
CY25812, and CY25814 products for other functions such as
clock multiplication of 1×, 2×, or 4× to generate a wide range
of Spread Spectrum output clocks from 4 to 128 MHz.