COMMUNICATION SEMICONDUCTORS
MX641
Dual SPM Detector
PRELIMINARY INFORMATION
DATA BULLETIN
Features
•
Two (12kHz / 16kHz) SPM Detectors on a
Single Chip
•
Detects 12 or 16kHz SPM Frequencies
•
‘Controlled’ (µC) & ‘Fixed’ Signal Sensitivity
µ
Modes
•
Selectable Tone Follower or Packet Mode
Outputs
•
High Speech-Band Rejection Properties
•
‘Output Enable’ Multiplexing Facility
CLOCK OUT
XTAL/CLOCK
XTAL/CLOCK
GENERATOR
XTAL
BUFFER
Applications
•
Call Charge Applications on PABX Line Cards
•
Remote Telephone Applications
CLOCK IN
CLOCK
DIVIDERS
INTERNAL
CLOCKS
V
DD
V
BIAS
V
SS
12kHz/16kHz
SYSTEM
Ch 1 AMP OUT
Ch1 AMP IN (-)
Ch 1
COMPARATOR
TONE FOLLOWER
MODE
Ch 1
OUTPUT
OUTPUT
SELECT
CIRCUITS
Ch1 AMP IN (+)
Ch 1
INPUT
AMPLIFIER
GAIN
ADJUST
INTERNAL
COMPARATOR
THRESHOLD
PRESET LEVEL
CHIP SELECT
SERIAL
DATA
12kHz/16kHz
SYSTEM
SERIAL
INPUT
LOGIC
LEVEL/
SYSTEM
SETTING
SERIAL
CLOCK
SYSTEM SELECT
Ch 2
INPUT
AMPLIFIER
GAIN
ADJUST
INTERNAL
COMPARATOR
THRESHOLD
Ch2 AMP IN (-)
Ch 2
BANDPASS
FILTER
Ch2 AMP IN (+)
Ch 2 AMP OUT
Ch 2
COMPARATOR
TONE FOLLOWER
MODE
The MX641 is a low-power, system-selectable Dual Subscriber Pulse Metering (SPM) Detector designed to
indicate the presence, on a telephone line, of either 12kHz or 16kHz telephone call-charge frequencies. It is
designed for PBX and PABX line-card and remote telephone installations. Under
µProcessor
control via a
common serial interface, each channel of the MX641 will detect call-charge pulses from a telephone line and
provide a digital output for recording, billing or security purposes. A common set of external components and
a stable 3.579545MHz Xtal/clock input ensures that the MX641 adheres accurately to most national “Must
and Must-Not” decode band-edges and threshold levels. For non-µProcessor systems a preset
sensitivity/system input allows external channel level and system setting
The digital output is pin-selectable to one of three modes:
(1) Tone Follower mode: logic level for the period of a correct decode.
(2) Packet mode: respond/de-respond after a cumulative period of tone or notone in a fixed (intrinsic
hardwired period that is not user controlled) period.
(3) High-impedance output: for device multiplexing.
The MX641 requires a 5V supply and is available in the following packages: 24-pin SOIC (MX641DW) and
24-pin PDIP (MX641P)
ã
2001 MX-COM, Inc.
www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
+
+
-
Ch 1
BANDPASS
FILTER
PULSE
GENERATOR
AND
DIVIDER
-
+
+
-
-
PULSE
MEASUREMENT
LOGIC
PULSE
LENGTH
LOGIC
PACKET
MODE
CHANNEL 1
OUTPUT
ENABLE
12kHz/16kHz
SYSTEM
OUTPUT
SELECT
CHANNEL 2
PULSE
GENERATOR
AND
DIVIDER
PACKET
MODE
PULSE
MEASUREMENT
LOGIC
PULSE
LENGTH
LOGIC
OUTPUT
SELECT
CIRCUITS
Ch 2
OUTPUT
Doc. # 20480115.004
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