The SKY72310-11 from Skyworks is a spur-free, fractional-N frequency synthesizer for high-performance Land Mobile Radio / Professional Mobile Radio (LMR/PMR) systems that operates from 50 MHz to 2.1 GHz. It provides ultra-fine frequency resolution, fast switching speed, and low phase-noise performance. This synthesizer consumes less than 14 mW of power @ 3V, 900 MHz providing extended battery life. The SKY72310-11 is available in a 24-pin, 4 x 4 mm surface-mount package and is ideal for rugged portable and mobile two-way radios used in business as well as and mission-critical applications.
The ultra-fine step size of less than 100 Hz allows this synthesizer to be used in very narrowband wireless applications. The synthesizer’s fine step size can compensate for crystal oscillator or intermediate frequency (IF) filter drift with proper temperature sensing or through control channels. As a result, crystal oscillators or crystals can replace temperature-compensated or ovenized crystal oscillators, reducing parts count and associated component cost. The device’s fine step size can also be used for Doppler shift corrections.
The unit operates with a three-wire, high-speed serial interface. A combination of large bandwidth, fine resolution, and the three wire interface allows for direct frequency modulation of the VCO. This supports any continuous phase, constant envelope modulation schemes such as Frequency Modulation (FM), Frequency Shift Keying (FSK), Minimum Shift Keying (MSK), or Gaussian Minimum Shift Keying (GMSK).
