Low Power High Performance RF Synth with Integrated VCO

CML Microcircuits is excited to announce that the CMX940 is available now to purchase through our distributors. The CMX940 is a low-power high performance Fractional-N PLL with fully-integrated wideband VCO and programmable output divider, generating RF signals over a continuous frequency range of 49 MHz to 2040 MHz.

It has two level-controlled single-ended RF outputs to support Tx and Rx sub-systems. A highly-configurable near noiseless clock multiplier can be used to minimise close-in phase noise and mitigate integer and fractional boundary spurious. The chip configuration is controlled by an SPI-compatible C-BUS serial interface.

Available in a 7 x 7 mm LGA-48 package, the CMX940 reduces component count and PCB board area, requiring only external loop filter and clock reference to provide a complete and very compact RF synthesizer solution.

Low operating voltage and low power consumption make it the perfect choice for a wide variety of portable and battery powered wireless applications, including digital narrowband two-way radio equipment compliant with ETSI PMR co-existence standards applicable under the Radio Equipment Directive.


  • RF output frequency 49 – 2040 MHz
  • Low current consumption 23 – 64 mA
  • Supply voltage 3.0 – 3.6 V
  • Low 1 Hz normalised PLL noise floor of -225 dBc/Hz
  • Typical phase noise -122 dBc/Hz, 10 kHz offset at 520 MHz
  • Dual programmable RF outputs
  • Low noise VCO -141 dBc/Hz, 1 MHz offset at 520 MHz
  • Automatic VCO selection and calibration
  • 16 and 24-bit fractional-N PLL modes
  • Digital lock detect
  • High comparison frequency up to 120 MHz
  • Very fast frequency switching <50 µs
  • Low level of spurious products -75 dBc (typ.)


  • PMR / LMR (including ETSI compliant radios)
  • Public Safety Radio
  • Wireless Data Modem
  • Wireless Microphone
  • Marine Radio
  • General Purpose RF / IF