The VT98521 is a 3.3V CMOS, clock multiplier integrated circuit. The device provides an excellent quality high frequency output clock from a lower frequency crystal or clock input. Tri-level selection inputs S0 and S1 are used to select any one of eight multipliers, stored in the on-board ROM, and apply it to the input to produce the desired output, up to 220 MHz. Phase Locked Loop (PLL) technology allows the device to use an input signal from an inexpensive crystal. When Output Enable (OE) is low, the clock output is in high impedance state.