DESCRIPTION

· The CMX138A is a half-duplex audio scrambler and sub-audio signalling processor IC designed for Analogue Two-way Radio applications. It is suitable for leisure radio markets such as FRS, MURS, PMR446, and GMRS. The device features a user-programmable frequency inversion audio scrambler, companding, and pre/de-emphasis, enabling simultaneous processing of Sub-audio and In-band signalling. It also includes an auxiliary ADC channel and an auxiliary DAC interface, with optional RAMDAC for transmitter power ramping. The device operates on a low power supply of 3.0V to 3.6V and is available in a 28-pin TSSOP package.

FEATURES

· Programmable Audio Scrambler
· Concurrent Audio/Signalling Operations
· Selectable Audio Processing Order
· Sub-audio Signalling: CTCSS, DCS
· Full Audio-band Processing: Pre and De-emphasis, Compandor, Scrambler, and Selectable 2.55/3 kHz Filters
· Auxiliary System Clock Output
· Tx Output for Single-point Modulation
· Low-power (3.0V to 3.6V) Operation
· Auxiliary ADC and Auxiliary DAC
· Flexible Powersave Modes
· C-BUS Serial Interface to Host µController
· Available in 28-pin TSSOP Package
· Two Analogue Inputs (Mic or Discriminator)

APPLICATIONS

· Analogue Two-way Radio Systems
· Leisure Radio Markets (FRS, MURS, PMR446, GMRS)