What this clock generator does and where it fits
The Cypress CY25814ZCT is a clock/frequency synthesizer and spread-spectrum clock generator with an integrated PLL. It accepts a clock, crystal, or resonator input and delivers a single CMOS clock output up to 128 MHz. The part includes a frequency modulator for spread-spectrum clock generation, making it suitable for EMI reduction in digital systems. The supply voltage is 2.97 V to 3.465 V or 3.135 V to 3.63 V, and it operates over the commercial temperature range of 0°C to 70°C.
128 MHz output and PLL — what that means for your clock tree
The 128 MHz maximum output frequency covers most high-speed serial interfaces (USB, Ethernet PHY reference clocks) and processor core clocks in the 100 MHz class. The PLL multiplies the input reference up to that frequency, and the divider/multiplier block gives you some flexibility to generate non-standard frequencies from a common crystal. Because the part is single-ended (no differential outputs), it is best suited for single-ended CMOS clock distribution on a PCB, not for differential pairs like LVDS or LVPECL.
Spread-spectrum modulation — the EMI angle
The CY25814ZCT includes a frequency modulator for spread-spectrum clock generation. This modulates the output frequency slightly to spread the radiated energy across a wider band, reducing peak EMI emissions. If you are designing a system that needs to pass FCC or CISPR radiated emissions tests — especially with a high-speed clock routed across a board — this part can help avoid the cost of additional shielding or ferrite beads. The modulation profile is internal; you do not need external components to enable it.
Package and footprint — 8-TSSOP
The part comes in an 8-TSSOP package (4.40 mm width, 0.65 mm pitch). It is a surface-mount device, so it runs through a standard reflow profile. The 8-pin footprint is small enough for space-constrained boards but still hand-solderable with a fine tip. The supplier device package is 8-TSSOP, same as the case code.
Lifecycle and compliance
Note that the RoHS status is listed as non-compliant — this part is not RoHS-compliant, so it cannot be used in products that require RoHS exemption-free compliance. For lead-free designs, check the CY25814ZC variant or a newer Cypress/Infineon clock generator.