CMX869BD2

Product Description

The CMX869B is a multi-standard modem for use in EPOS terminals and telephone based information and telemetry systems. This highly integrated single-chip modem IC provides the functions needed to construct a ITU V.32 bis automode modem or a V.22 bis, V.22, V.21 and Bell 202, Bell 103 compatible modem operating under the control of external host timing for EPOS and other proprietary protocols.

The V.32 bis automode-modem provides operation from 14400 bps with automatic fallback through to 4800 bps, retrain, rate re-negotiation and automatic detection of V.22 and V.22 bis modems.

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 µController when line voltage reversal or ringing is detected.

The CMX869B features a software controlled output to drive a hook switch relay and a ring detector block that continues to function when the device is in Powersave mode. When a line voltage reversal or ringing signal is detected, the ring detector circuit provides an interrupt that can wake up the host µController.

Line input and line outputs can be single-ended or differential and the line-output amplifier is capable of directly driving into a low-impedance transformer or opto-isolated DAA. The hybrid and gain control circuits are integrated on chip, requiring only passive external components to build a 2- or 4-wire line interface.

Host control and data transfer is via a simple, high-speed serial bus that operates in normal and Powersave modes and which is compatible with popular µC serial interfaces. An embedded USART accepts multi-format asynchronous data with V.14 support, or allows unformatted synchronous data or HDLC framed data to be received or transmitted. Data transfer can be in either an 8- or 16-bit format.

The CMX869B operates from a single 3.3V supply over a temperature range of -40°C to +85°C and is available in 24-pin TSSOP (E2) and SOIC (D2) packages.

Features

• V.32 bis/V.32/V.22 bis/V.22 Automode Modem
• V.22 bis/V.22 Manual Mode (2400, 1200 bps)
• V.23 (1200/75, 1200/1200, 75, 1200 bps FSK)
• Bell 202 (1200/150, 1200/1200, 150, 1200 bps FSK)
• V.21 or Bell 103 (300/300 bps FSK)
• High Performance DTMF Codec
• Single/Dual Tone Encoders and Decoders
• Powersave Standby Mode
• Asynchronous, Synchronous and HDLC Modes