CMX868A CML Microcircuits Low Power COMMUNICATION SEMICONDUCTORS V.22 bis Modem D/868A/3 May 2008 Features Applications V.22 bis 2400/2400 bps QAM Telephone Telemetry Systems V.22, Bell 212A 1200/1200 or 600/600 bps DPSK Remote Utility Meter Reading V.23 1200/75, 1200/1200, 75, 1200 bps FSK Security Systems Bell 202 1200/150, 1200/1200, 150, 1200 bps FSK Industrial Control Systems V.21 or Bell 103 300/300 bps FSK Electronic Cash Terminals DTMF/Tones Transmit and Receive Pay-Phones Powersave Standby Mode Set-Top Boxes 1. Brief Description The CMX868A is a multi-standard modem for use in telephone based information and telemetry systems. Control of the device is via a simple high speed serial bus, compatible with most types of C serial interface. The data transmitted and received by the modem is also transferred over the same serial bus. On-chip programmable Tx and Rx USARTs meeting the requirements of V.14 are provided for use with asynchronous data and allow unformatted synchronous data to be received or transmitted as 8-bit words. A high-quality DTMF decoder with excellent immunity to falsing on voice and a standard DTMF encoder are included. Alternatively, these blocks can be used to transmit and detect user-specific, programmed single and dual-tone signals, call progress signals or modem calling and answering tones. Flexible line driver and receive hybrid circuits are integrated on chip, requiring only passive external components to build a 2 or 4-wire line interface. The device also features a hook switch relay drive output and a Ring Detector circuit which continues to function when the device is in the Powersave mode, providing an interrupt which can be used to wake up the host Controller when line voltage reversal or ringing is detected. The CMX868A operates from a single 2.7 to 5.5V supply over a temperature range of -40C to +85C and is available in 24-pin TSSOP, SOIC and DIP packages. 2008 CML Microsystems Plc Low Power V.22 bis Modem CMX868A CONTENTS Section Page 1. Brief Description ..................................................................................... 1 2. Block Diagram......................................................................................... 3 3. Signal List................................................................................................4 4. External Components............................................................................. 5 4.1 Ring Detector Interface ............................................................. 6 4.2 Line Interface.............................................................................. 7 5. General Description.............................................................................. 10 5.1 Tx USART.................................................................................. 11 5.2 FSK and QAM/DPSK Modulators ........................................... 12 5.3 Tx Filter and Equaliser ............................................................ 13 5.4 DTMF/Tone Generator ............................................................. 13 5.5 Tx Level Control and Output Buffer....................................... 13 5.6 Rx DTMF/Tones Detectors ...................................................... 14 5.7 Rx Modem Filtering and Demodulation................................. 15 5.8 Rx Modem Pattern Detectors and Descrambler ................... 16 5.9 Rx Data Register and USART ................................................. 16 5.10 C-BUS Interface........................................................................ 18 5.10.1 General Reset Command ........................................... 18 5.10.2 General Control Register ........................................... 20 5.10.3 Transmit Mode Register............................................. 22 5.10.4 Receive Mode Register............................................... 26 5.10.5 Tx Data Register.......................................................... 28 5.10.6 Rx Data Register ......................................................... 28 5.10.7 Status Register............................................................ 29 5.10.8 Programming Register ............................................... 32 6. Application Notes ................................................................................. 35 6.1 V.22 bis Calling Modem Application ...................................... 35 6.2 V.22 bis Answering Modem Application ............................... 36 6.3 Reference Diagrams ................................................................ 37 7. Performance Specification................................................................... 38 7.1 Electrical Performance............................................................ 38 7.1.1 Absolute Maximum Ratings....................................... 38 7.1.2 Operating Limits ......................................................... 38 7.1.3 Operating Characteristics.......................................... 39 7.2 Packaging ................................................................................. 46 It is always recommended that you check for the latest product datasheet version from the Datasheets page of the CML website: www.cmlmicro.com . 2008 CML Microsystems Plc 2 D/868A/3