CML Microcircuits
COMMUNICATION SEMICONDUCTORS
CMX838
FRS/PMR446/GMRS
Family Radio Processor
D/838/8 September 2003
Provisional Issue
Features and Applications
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Advanced one-of-any CTCSS
subaudio 50 tone processor
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FRS, PMR446 and GMRS RF
channels
Configurable charge pump
Audio call tone generator
Audio processing
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Fast decode time
IRQ on any / all valid tones
Fast scan, group calling, auto
response tone select and
Tone Cloning™ support
Supply Independent output level
RF Synthesizer
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Signal source and external function
switches
Low power, 3V to 5V supply
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Mic amplifier
Pre/De-emphasis
Limiter with Supply Independent
output level
Post limiter filtering
Mic, Rx, and Tx digital gain controls
Single and Dual Tx outputs
Powersave and sleep modes
Serial control interface
AUX I/O
RXOUT
MICOUT
AUDIO PROCESSOR
MICIN
RXIN
GENERAL PURPOSE
TIMER AND TONE
GENERATOR
PROGRAMMABLE SUBAUDIO PROCESSOR
MODULATION OUTPUT
SELECT AND LEVEL
CONTROL
TXMOD1
TXMOD2
IRQ
RPLY DATA
C-BUS
TIMING
GENERATION
CMD DATA
SERIAL CLOCK
CS
REFIN
XTAL
-RFIN
XTAL
XTAL
+RFIN
ISET
RF SYNTHESIZER
VDD
CPOUT
BIAS
SVDD
SVSS
A
VBIAS
VSS
S
The highly integrated CMX838 Family Radio Processor includes subaudio, audio, and synthesizer functions
to serve as the core engine for low cost, high performance FRS, PMR446, and GMRS radio designs. Its
flexibility supports both simple and advanced multi-channel radios without cost penalties. Integrated Tx
voltage reference and baseband clock generation circuits eliminate the need for external components. The
CMX838’s features directly supports advanced end product functions such as: group calling, scanning,
automatic scanner response tone setup, and Tone Cloning™.
By using the CMX838 one global radio design can support multiple standards and markets.
Controlled via a serial interface (C-BUS) the Family Radio Processor operates from a 3V to 5V supply and is
available in 28-pin TSSOP (CMX838E1) and 28-pin SOIC (CMX838D1) packages.
© 2003 CML Microsystems Plc
