The ADF4150 allows implementation of fractional-N or integer-N phase-locked loop (PLL) frequency synthesizers if used with an external Voltage Controlled Oscillator (VCO), loop filter and external reference frequency. The ADF4150 is for use with external VCO parts and is software compatible with the ADF4350. The VCO frequency can be divided-by 1/2/4/8 or 16 to allow the user to generate RF output frequencies as low as 31.25 MHz. For applications that require isolation the RF output stage can be muted. The mute function is both pin and software controllable. Control of all the on-chip registers is through a simple 3-wire interface. The device operates with a power supply ranging from 3.0 V to 3.6 V and can be powered down when not in use.