The 343 is a low cost, triple-output, field programmable clock synthesizer. The 343 can generate three output frequencies from 250 kHz to 200 MHz, using up to three independently configurable PLLs. The outputs may employ Spread Spectrum techniques to reduce system electro-magnetic interference (EMI). Using IDT's VersaClock™ software to configure the PLL and output, the 343 contains a One-Time Programmable (OTP) ROM to allow field programmability. Using Phase-Locked Loop (PLL) techniques, the device runs from a standard fundamental mode, inexpensive crystal, or clock. It can replace multiple crystals and oscillators, saving board space and cost. The device also has a power down feature that tri-states the clock outputs and turns off the PLLs when the PDTS pin is taken low. The 343 is also available in factory-programmed custom versions for high-volume applications.