The devices described in this document are typically used as lowpower, phaselocked loop frequency synthesizers. When combined with an external lowpass filter and voltagecontrolled oscillator, these devices can provide all the remaining functions for a PLL frequency synthesizer operating up to the device's frequency limit. For higher VCO frequency operation, a down mixer or a prescaler can be used between the VCO and the synthesizer IC. These frequency synthesizer chips can be found in the following and other applications: