CML - Marine Comms - CMX885

The CMX885 is a half-duplex, audio, signalling and data processing IC for use in Marine VHF radio systems.

Comprehensive audio processing facilities include complete voice-band processing, filtering, pre- or de-emphasis and frequency inversion scrambling. The audio processing feature operating order is selectable. Signal routing and filtering is included to assist host µC based signal encoding/decoding applications.

A 1200bps Digital Selcall (DSC)/Automatic Transmitter Identification System (ATIS) modem with protocol support and National Oceanic and Atmospheric Administration (NOAA) National Weather Radio (NWR) decoding are supported.

A DTMF encoder/decoder, a full complement of auxiliary ADCs and DACs and dual synthesised clock outputs are included in this low power PMR processor.
The device also has flexible powersaving modes and is available in 48-pin VQFN and LQFP packages.

Block Diagram


  • Concurrent Audio, Signalling and Data Operations
  • Complete Audio Band Processing:
    • Selectable Audio Processing Order
    • Pre and De-emphasis
    • Selectable 2.55/3.0 kHz Filtering
    • Limiter
  • Programmable Voice-band Scrambler
  • In-band Signalling:
    • DTMF
    • NOAA NWR
  • DTMF and Audio Tone Encoder
  • Dual Auxiliary ADC with 4 Multiplexed Inputs
  • C-BUS Serial Interface to Host µController
  • Four x Auxiliary DACs
  • Dual Programmable System Clock Outputs
  • Tx Outputs for Single or Two-point Modulation
  • Three x Analogue Inputs
  • Digital Gain Adjustment
  • DSC/ATIS Modem for Marine Applications
  • Default 3.6864MHz Xtal/Clock
  • Low Power Operation with Flexible Powersave Modes
  • Compact VQFN and LQFP Packages


  • Marine VHF Radio and/or Marine Safety Systems

Supply Requirement:

  • 3.3V power supply