CML Microcircuits
COMMUNICATION SEMICONDUCTORS
CMX661
PAIR GAIN DUAL
SPM DETECTOR
Provisional Information
D/661/3 July 2002
Features
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Two (12kHz/16kHz) SPM Detectors
Standard 3.579545MHz Xtal
Selectable Bandwidth Limits
Excellent Speech-Band Rejection
Low Power 3.0V to 5.0V Operation
Applications
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Pair-Gain Systems
Out-of-Band Signalling Systems
Call Charge Applications in
PBX and PABX Line Cards
1.1
Brief Description
The CMX661 is a low power, Dual Subscriber Pulse Metering (SPM) Detector –
two detectors on a single
chip
– to indicate the presence on a telephone line of either 12kHz or 16kHz telephone call charge
frequencies. The detection frequency and bandwidth are common to both detectors and may be
externally selected. The detection sensitivity is set independently for each channel by external
components and the detector outputs can be set to a high impedance state for device multiplexing
requirements in PBX and PABX line card applications.
Flexibility of decode bandwidth settings allows the CMX661 to operate in systems where the SPM
generation is not necessarily perfectly accurate or stable. External hardwired selection of functionality
economises on the number of host µC I/O control lines required, whilst the rapid response and de-
response times of the CMX661 permit flexible tone length qualification by the host µC.
The CMX661 offers low (3.0V) operating voltage and power, consuming
≈750µA
at 3V. It is available in
low-cost 16-pin plastic DIL and SOIC packages.
©
2002 CML Microsystems Plc
CMLMICRO [ CML MICROCIRCUITS ]
