CMX269AE2 MX-COM, Inc., CMX269AE2 Datasheet

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CMX269AE2

Manufacturer Part Number
CMX269AE2
Description
1200/2400/4800bps MSK modem
Manufacturer
MX-COM, Inc.
Datasheet
Features
The CMX469A is a full-duplex pin-selectable 1200/2400/4800bps Minimum Shift Key (MSK) Modem for FM
radio links. The mark and space frequencies are 1200/1800, 1200/2400, and 2400/4800Hz respectively.
Tone frequencies are phase continuous; transitions occur at the zero crossing point. The use of a common
Xtal oscillator with a choice of two clock frequencies (1.008MHz or 4.032MHz) provides data-rate, transmit
frequencies, and RX/TX synchronization. The transmitter and receiver operate entirely independently
including individual section powersave functions.
The CMX469A includes on-chip circuitry for Carrier Detect and RX Clock Recovery, both of which are made
available at output pins. RX, TX and Carrier Detect circuits contain bandpass filters to provide high quality
signals to their respective paths. The carrier detect time constant is set by an external capacitor, which may
be selected to optimize performance in high-noise environments.
High sensitivity and good bit-error-rate performance can be achieved even under adverse signal conditions.
The CMX469A operates with a 3.0V to 5.5V supply and is available in the following packages:
24-pin TSSOP (CMX469AE2), 20-pin SOIC (CMX469AD3), and 22-pin PDIP (CMX469AP6).
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
1999 MX-COM, Inc.
Selectable Data Rates
Full-Duplex MSK
RX and TX Bandpass Filters
Clock Recovery and Carrier Detect
Capabilities
Pin Selected Xtal/Clock Inputs
1200/2400/4800 bps
1.008MHz or 4.032MHz
www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054
DATA BULLETIN
CMX469A
All trademarks and service marks are held by their respective companies.
Applications
Radio and General Applications
Data-Over-Radio
PMR/Cellular Signaling
Portable Data Terminals
Narrowband Coax Data Channels
Two Way Radio (MPT1327) Signaling
Personal/Cordless Telephone
1200/2400/4800bps
PRELIMINARY INFORMATION
MSK Modem
Doc. # 20480191.002

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CMX269AE2 Summary of contents

Page 1

... The CMX469A operates with a 3.0V to 5.5V supply and is available in the following packages: 24-pin TSSOP (CMX469AE2), 20-pin SOIC (CMX469AD3), and 22-pin PDIP (CMX469AP6). 1999 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 ...

Page 2

... Operating Limits ....................................................................................................................... 11 6.1.3 Operating Characteristics ......................................................................................................... 12 6.1.4 Timing....................................................................................................................................... 14 6.2 Packages........................................................................................................................... 17 MX-COM, Inc. reserves the right to change specifications at any time without notice. 1999 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 2 CMX469A PRELIMINARY INFORMATION Contents All trademarks and service marks are held by their respective companies ...

Page 3

... MSK Modem 1. Block Diagram 1999 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 3 CMX469A PRELIMINARY INFORMATION Figure 1: Block Diagram All trademarks and service marks are held by their respective companies. ...

Page 4

... RX Signal Sync Out 1999 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 4 Signal Type The input to the on-chip inverter, for use with either a 1.008MHz or a 4.032MHz Xtal or external clock. ...

Page 5

... Select Pin 4800 Select Pin Data Rate (bps) Table 3: Operational Data Rate Configuration 1999 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 5 Signal Type A logic ‘1’ on this pin selects the 1200bps option. ...

Page 6

... Figure 3: Recommended External Components for D3 package Component Notes Table 4: Recommended External Components 1999 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 6 Value Component Notes C5 1.0M 33.0pF C6 1 1.0µ ...

Page 7

... Carrier Detect Out. A Bandpass output is also available from the output of the first Rx filter stage, but will require buffering before use. 1999 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 ...

Page 8

... Synchronous and asynchronous interface can be successfully interfaced for applications requiring the advantages of both. This typically involves the use of data buffering and retiming circuits to resolve the timing and pacing issues. 1999 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 ...

Page 9

... Figure 6: Typical Variation of Bit Error Rate with Input Level 1999 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 9 TX SIGNAL O/P TELEPHONE BUFFER ...

Page 10

... Figure 7: RX Bit-Error-Rate vs. Signal-to-Noise Ratio 1999 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 10 CMX469A SNR (dB) BIT RATE BANDWIDTH (lin scale) All trademarks and service marks are held by their respective companies ...

Page 11

... A Xtal frequency of 1.008MHz (1200/2400 baud only) or 4.032MHz is required for correct operation. A frequency tolerance of 0.1% is recommended, but ultimately the tolerance selected will depend upon system requirements. 1999 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 ...

Page 12

... Carrier Detect Sensitivity Probability of CD being high after bit 16: With SNR = 12dB With 230mVRMS Noise and No Signal 1999 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 12 = 3. ...

Page 13

... RMS (1200/2400 baud operation) or 8kHz (4800 baud operation). See Section 3, Note 2 for details on optimizing noise immunity. 10. For an unmodulated carrier 1999 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 13 Notes Min ...

Page 14

... LOGIC '1' RX SIGNAL I/P 1200 BPS 1 RX SYNC O/P (1200Hz CLOCKED DATA O/P 0 Figure 9: Receiver Timing Diagram: 1200bps 1999 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 14 Note Min. t SYNC t 2.0 ESET t 1 2.0 ...

Page 15

... Figure 10: Transmitter Timing: 2400bps LOGIC '1' RX SIGNAL I/P 2400 BPS 1 RX SYNC O/P (2400Hz RDR 1 CLOCKED DATA O/P 0 1999 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 15 Note Min. t SYNC t 2.0 ESET t 1 2.0 DSET t 2 ...

Page 16

... Figure 12: Transmitter Timing: 4800bps LOGIC '1' RX SIGNAL I/P 4800 BPS 1 RX SYNC O/P (4800Hz RDR 1 CLOCKED DATA O/P 0 1999 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 16 Note Min. t SYNC t 2.0 ESET t 1 2.0 DSET t 2 ...

Page 17

... A ALTERNATIVE PIN LOCATION MARKING PIN Figure 15: 20-pin SOIC Mechanical Outline: Order as part no. CMX469AD3 1999 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 ...

Page 18

... MARKING PIN Figure 16: 24-pin TSSOP Mechanical Outline: Order as part no. CMX469AE2 1999 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 All trademarks and service marks are held by their respective companies. ...

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