DATA BULLETIN
CMX631A
Low Voltage
SPM Detector
PRELIMINARY INFORMATION
Features
• Detects 12kHz or 16kHz SPM
Frequencies
• Tone Follower and Packet Mode
Outputs
• High Speech-Band Rejection
Properties
• Low Power Operation (3.0V < 0.8mA)
Applications
• Call Charge Applications on PABX Line
Cards
• Complex and/or Simple telephone
Systems
• Remote Telephone/Payphones
XTAL/CLOCK
XTAL
XTAL/CLOCK
OSCILLATOR
VDD
VBIAS
VSS
SYSTEM (12kHz/16kHz)
INPUT AMP
SIGNAL IN (-) -
+
SIGNAL IN (+)
AMP OUT
12kHz/16kHz
+20dB
CLOCK OUT
CLOCK IN
SYSTEM
CLOCK
DIVIDERS
TONE FOLLOWER
OUTPUT
TONE
FOLLOWER
LOGIC
LEVEL DETECTOR
32
1
DIVIDER
PERIOD
MEASURE
SYSTEM
PACKET MODE
OUTPUT
PACKET
TONE
LOGIC
The CMX631A is a low-power, system-selectable Subscriber Pulse Metering (SPM) detector that indicates the
presence of both 12kHz or 16kHz telephone call-charge frequencies on a telephone line.
Deriving its input directly from the telephone line, input amplitude/sensitivities are component adjustable to the
user's national ‘Must/Must-Not Decode’ specifications via an on-chip input amplifier. The 12kHz and 16kHz
frequency limits are accurately defined by the use of an external 3.579545MHz telephone-system Xtal or
clock-pulse input.
The CMX631A demonstrates exceptional 12kHz and 16kHz performance in the presence of both voice and
noise. This device may operate from a single or differential analog signal input, from which two individual
logic outputs will be produced; a Tone Follower Output or a Packet Mode Output.
This system (12kHz/16kHz) selectable integrated circuit, requires a 2.7V to 5.5V power supply, which may be
line-powered, is available in the following packages: 24-pin SSOP (CMX631AD5), 16-pin SOIC
(CMX631AD4), and 16-pin PDIP (CMX631AP3). Additional package styles may be available to meet specific
design requirements.
© 1999 MX•COM Inc.
www.mxcom.com Tele: 800 638-5577 336 744-5050 Fax: 336 744-5054
Doc. # 20480177.004
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA All trademarks and service marks are held by their respective companies.