CML launches fully integrated RF synthesizer for low-power applications

     CML Microcircuits presents the CMX940, a fully integrated, Fractional N RF synthesizer with a voltage controlled oscillator (VCO) that delivers low phase noise and superior stray noise performance in a low-power, single-chip solution. The CMX940 has surpassed industry-set performance standards to enable the next generation of dedicated mobile radios (PMR), data modems, Marine radios and other wireless systems.

     To enable high performance and flexibility with a low-power solution, CML employs a two-loop architecture with highly configurable reference paths, including a separate phase-locked loop (PLL) and VCO to minimize close-in phase noise and reduce integer and fractional boundary stray noise.

     Managing phase noise and stray noise performance is important to meet international standards, including ETSI, such as EN 300 113 and EN 300 086, which are mandatory radio standards for narrowband communication systems. The CMX940 includes a number of design innovations, one of which is a near-noise-free clock multiplier technology that delivers the high performance required to meet these stringent standards.

     The CMX940 generates RF signals in the 49 MHz to 2040 MHz continuous frequency range and has dual single-ended RF outputs to support receiver (Rx) and transmitter (Tx) subsystems, requiring only an external loop filter and clock reference for a compact and high-quality local oscillator (LO).

     Many other synthesizers for these applications are based on a PLL IC, and to implement a VCO requires a large number of external discrete components that take up valuable PCB space. CML's new solution is designed to reduce component count and board area through higher chip integration, eliminate VCO tolerances, and accelerate time-to-market.

     At 500MHz carrier frequency and an offset of 12.5kHz, the typical phase noise is -124dBc/Hz, and the stray noise is better than -75 DBC. The CMX940 operates at 3.0V to 3.6V and consumes 23mA to 64mA depending on the device configuration, making it ideal for portable devices and battery-powered applications.