COMMUNICATION SEMICONDUCTORS

MX641

DATA BULLETIN

Dual SPM Detector

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ã2001 MX-COM, Inc.

www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054

Doc. # 20480115.004

4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA

All trademarks and service marks are held by their respective companies.

PRELIMINARY INFORMATION

Features

Applications

• Two (12kHz / 16kHz) SPM Detectors on a

Single Chip

• Detects 12 or 16kHz SPM Frequencies

• ‘Controlled’ (µµµµC) & ‘Fixed’ Signal Sensitivity

Modes

• Selectable Tone Follower or Packet Mode

Outputs

• High Speech-Band Rejection Properties

• ‘Output Enable’ Multiplexing Facility

• Call Charge Applications on PABX Line Cards

• Remote Telephone Applications

+

-

Ch 2

BANDPASS

FILTER

Ch 2

INPUT

AMPLIFIER

CHANNEL 2

CHANNEL 1

Ch2AMP OUT

Ch2 AMP IN (-)

Ch2 AMP IN (+)

Ch 2

OUTPUT

Ch 2

COMPARATOR

PULSE

GENERATOR

AND

DIVIDER

PULSE

MEASUREMENT

LOGIC

PULSE

LENGTH

LOGIC

OUTPUT

SELECT

CIRCUITS

Ch 1

BANDPASS

FILTER

XTAL/CLOCK

GENERATOR

XTAL/CLOCK

CLOCK OUT

CLOCK IN

BUFFER

CLOCK

DIVIDERS

LEVEL/

SYSTEM

SETTING

SERIAL

INPUT

LOGIC

SERIAL

DATA

SERIAL

CLOCK

PRESET LEVEL

SYSTEM SELECT

Ch 1

INPUT

AMPLIFIER

12kHz/16kHz

SYSTEM

12kHz/16kHz

SYSTEM

12kHz/16kHz

SYSTEM

TONE FOLLOWER

MODE

TONE FOLLOWER

MODE

PACKET

MODE

PACKET

MODE

INTERNAL

CLOCKS

INTERNAL

COMPARATOR

THRESHOLD

INTERNAL

COMPARATOR

THRESHOLD

GAIN

ADJUST

GAIN

ADJUST

Ch1AMP OUT

Ch1 AMP IN (-)

Ch1 AMP IN (+)

Ch 1

OUTPUT

OUTPUT

SELECT

Ch 1

COMPARATOR

PULSE

GENERATOR

AND

DIVIDER

PULSE

MEASUREMENT

LOGIC

PULSE

LENGTH

LOGIC

OUTPUT

SELECT

CIRCUITS

XTAL

OUTPUT

ENABLE

CHIP SELECT

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)