The ICS557-03 is a spread spectrum clock generator that supports PCI-Express and Ethernet requirements. The device is used for PC or embedded systems to substantially reduce electromagnetic interference (EMI). The device provides two differential (HCSL) spread spectrum outputs. The spread type and amount are configured via select pin. Using IDT's patented Phase-Locked Loop (PLL) techniques, the device takes a 25 MHz crystal input and produces two pairs of differential outputs at 25 MHz, 100 MHz, 125 MHz or 200 MHz clock frequencies for HCSL, and 25 MHz or 100 MHz for LVDS.