CMX469AE2 CML Microcircuits, CMX469AE2 Datasheet

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CMX469AE2

Manufacturer Part Number
CMX469AE2
Description
1200/2400/4800 Baud FFSK Modem
Manufacturer
CML Microcircuits
Datasheet
D/469A/2 May 2001
Features
1.1
2001 Consumer Microcircuits Limited
Separate Rx and Tx Enable Functions
Full-Duplex FFSK/MSK Modem with
Pin Selectable Data Rates:
Pin Selectable Xtal/Clock Inputs:
Clock Recovery Facility
Carrier Detect Facility
Low Power Operation (2.0mA typ. at 3.0V)
1200, 2400 or 4800 Baud
1.008MHz or 4.032MHz
Brief Description
The CMX469A is a single-chip CMOS LSI circuit which operates as a full-duplex 1200, 2400 or
4800 baud FFSK/MSK modem. The mark and space frequencies are 1200/1800, 1200/2400 and
2400/4800 Hz respectively. Tone frequencies are phase continuous; transitions occur at the zero
crossing point. A common Xtal oscillator with a choice of two clock frequencies (1.008MHz or
4.032MHz) provides baud-rate, transmit frequencies, and Rx and Tx synchronization.
The transmitter and receiver operate entirely independently, including the individual section
powersave functions. The CMX469A includes on-chip circuitry for Carrier Detect and Rx Clock
recovery, both of which are made available as output pins. Rx, Tx and Carrier Detect paths
contain bandpass filters to optimise signal conditions in each section of the modem. The
CMX469A demonstrates good sensitivity and bit-error-rate under adverse signal conditions. The
Carrier Detect time constant is set by an external capacitor, so that the product's performance
can be optimised in high noise environments. This low-power device operates from a single
supply between 2.7V and 5.5V, requires few external components and is available in a wide
variety of plastic packages.
Applications
Data-Over Radio
Personal/Cordless Telephone
Radio and General Applications
Narrowband Coax Data Channels
Two Way Radio (MPT1327) Signalling
Portable Data Terminals
1200/2400/4800 Baud
FFSK/MSK Modem
CMX469A
Provisional Issue

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CMX469AE2 Summary of contents

Page 1

D/469A/2 May 2001 Features Full-Duplex FFSK/MSK Modem with Separate Rx and Tx Enable Functions Pin Selectable Data Rates: 1200, 2400 or 4800 Baud Pin Selectable Xtal/Clock Inputs: 1.008MHz or 4.032MHz Clock Recovery Facility Carrier Detect Facility Low Power Operation (2.0mA ...

Page 2

Baud FFSK/MSK Modem Section 1.0 Features and Applications.......................................................................2 1.1 Brief Description .......................................................................................2 1.2 Block Diagram ...........................................................................................4 1.3 Signal List...................................................................................................5 1.4 External Components ...............................................................................7 1.5 General Description ..................................................................................8 1.6 Application Notes......................................................................................9 1.7 Performance Specification.....................................................................10 1.7.1 Electrical Performance..............................................................10 1.7.2 Packaging....................................................................................16 2001 ...

Page 3

Baud FFSK/MSK Modem 1.2 Block Diagram 2001 Consumer Microcircuits Limited Figure 1 Block Diagram 4 CMX469A D/469A/2 ...

Page 4

Baud FFSK/MSK Modem 1.3 Signal List CMX469A Pin Pin Pin No. No. No ...

Page 5

Baud FFSK/MSK Modem CMX469A Pin Pin Pin No. No. No SIGNAL I DETECT TIME ...

Page 6

Baud FFSK/MSK Modem 1.4 External Components Notes may be decoupled to V BIAS pin. For input signals referenced The performance of the Carrier Detect function will be affected by the nature of the noise ...

Page 7

Baud FFSK/MSK Modem 1.5 General Description The CMX469A has two sections, apart from the Xtal oscillator circuit and clock dividers. These sections may be independently powersaved. Transmitter The transmitter is enabled by taking Tx EnableN low. Serial data applied ...

Page 8

Baud FFSK/MSK Modem 1.6 Application Notes Rx Enable The control of the relevant outputs with reference to the Rx Enable input is described below: Rx Enable Rx Function ‘1’ Enabled ‘0’ Powersave After enabling the Receiver, a time of ...

Page 9

Baud FFSK/MSK Modem 1.7 Performance Specification 1.7.1 Electrical Performance Absolute Maximum Ratings Exceeding these maximum ratings can result in damage to the device. Supply ( Voltage on any pin Current into ...

Page 10

Baud FFSK/MSK Modem Operating Limits Correct operation of the device outside these limits is not implied. Supply ( Operating Temperature Xtal Frequency Note 1: A Xtal frequency of 1.008MHz (1200/2400 baud only) or 4.032MHz ...

Page 11

Baud FFSK/MSK Modem Carrier Detect Sensitivity Probabilty of CD being High after bit 16: with SNR = 12dB with 230mVrms Noise and No Signal Transmitter Output Tx Output Level Output Level Variation for 1200/1800Hz or 1200/2400Hz or 2400/4800Hz Output ...

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Baud FFSK/MSK Modem Interface Timing Diagrams Tx ENABLE Tx SYNC DC = Don't Tx DATA DV = Data Valid OPEN CIRCUIT 1200 BAUD Tx OUTPUT OPEN CIRCUIT 2400 BAUD Tx OUTPUT TX DATA must be valid at the time ...

Page 13

Baud FFSK/MSK Modem 1.7.1 Electrical Performance (continued) Interface Timings t Tx Delay, Signal to Disable Time ESET t Data Set-Up Time DSET t Data Hold Time Delay to O/P Time TXD t Tx Data Rate Period ...

Page 14

Baud FFSK/MSK Modem Figure 7 Typical Rx Bit Error Rate vs Signal-to-Noise Ratio 2001 Consumer Microcircuits Limited 15 CMX469A D/469A/2 ...

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... Baud FFSK/MSK Modem 1.7.2 Packaging Figure 8 D3 Mechanical Outline: Order as part no. CMX469AD3 Figure 9 E2 Mechanical Outline: Order as part no. CMX469AE2 2001 Consumer Microcircuits Limited 16 CMX469A D/469A/2 ...

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Baud FFSK/MSK Modem Figure 12 P6 Mechanical Outline: Order as part no. CMX469AP6 Handling precautions: This product includes input protection, however, precautions should be taken to prevent device damage from electro-static discharge. CML does not assume any responsibility for ...

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