Low-power synthesizer features frequency-shift keying modulation

New from Texas Instruments, the LMX2571 is a low-power, high-performance, wideband PLLatinum RF synthesizer that integrates a delta-sigma fractional N PLL, multiple core voltage-controlled oscillator (VCO), programmable output dividers and two output buffers. The VCO cores work up to 5.376GHz resulting in continuous output frequency range of 10MHz to 1344MHz. The synthesizer can also be used with an external VCO. To that end, a dedicated 5V charge pump and an output divider are available for this configuration. A novel programmable multiplier is also incorporated to help improve spurs, allowing the system to use every channel even if it falls on an integer boundary. The output has an integrated SPDT switch that can be used as a transmit / receive switch in FDD radio application. Both outputs can also be turned on to provide 2 outputs at the same time. The LMX2571 supports direct digital FSK modulation through programming or pins. Discrete level FSK, pulse shaping FSK, and analog FM modulation are supported. A new FastLock technique can be used allowing the user to step from one frequency to the next in less than 1.5ms even when an external VCO is used with a narrow band loop filter, says the company.