CMX639
Consumer / Commercial
CVSD Digital Voice Codec
D/639/2 November 2000
Provisional Issue
Features
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Applications
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Single Chip Full Duplex CVSD codec
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Integrated Input and Output Filters
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Robust Coding for Wireless Links
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Programmable Sampling Clocks
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3 and 4 bit Companding Algorithms
Low Power/Small Size for Portable Devices
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1.9mA/2.75mA typ. @ 3.0V/5.0V
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3.0V to 5.5V Operation
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Powersave Mode
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Consumer and Business Handheld
Devices
Digital Voice Appliances
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Spread Spectrum Wireless
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Cordless Phones
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Voice Recording and Storage
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Delay Lines
Time Domain Scramblers
Multiplexers and Switches
1.1
Brief Description
The CMX639 is a Continuously Variable Slope Delta Modulation (CVSD) full duplex CODEC for use in
consumer and commercial digital voice communication systems. With its robust and selectable coding
algorithms, low cost, very low power, and small size, the CMX639 is ideal for use in a wide variety of
consumer and business digital voice applications. Its completely integrated CODEC simplifies design and
eliminates the costs, complexity and risk of external filters and software algorithms.
8kbps to 128kbps data/sampling clock rates are supported both via external clock signals or internally
generated, programmable clocks. Internal data/sampling clocks are derived from an on-chip reference
oscillator that uses an external clock crystal. An internal data/sampling clock output signal is provided to
synchronize external circuits, if desired. Multiplexer applications are also well supported by the encoder
output’s three-state/high impedance enable feature.
The CMX639 operates from 2.7V to 5.5V supplies and is available in the following packages: 24-pin TSSOP
(CMX639E2), 16-pin SOIC (CMX639D4) and 22-pin PDIP (CMX639P6).
©
2000
Consumer Microcircuits Limited
CMLMICRO [ CML MICROCIRCUITS ]
