CMX868AD2

Overview

The CMX868AD2 is a low-power V.22 bis modem integrated circuit manufactured by CML Microcircuits, designed for telephone-based information and telemetry systems. It supports multiple standards including V.22 bis (2400/2400 bps QAM), V.22/Bell 212A (1200/1200 or 600/600 bps DPSK), V.23 (1200/75, 1200/1200, 75/1200 bps FSK), Bell 202 (1200/150, 1200/1200, 150/1200 bps FSK), and V.21/Bell 103 (300/300 bps FSK). The device operates on a single 2.7V to 5.5V supply over a temperature range of -40°C to +85°C. It features programmable Tx/Rx USARTs, DTMF/Tone generation and detection, flexible line drivers, and a ring detector with interrupt capability.

Feature Summary

• Multi-standard modulation support for QAM, DPSK, and FSK protocols
• Integrated high-speed serial C-BUS interface for microcontroller control
• Programmable transmit and receive USARTs compliant with V.14 requirements
• On-chip DTMF encoder/decoder and programmable tone generator/detector
• Flexible 2-wire and 4-wire line interface circuits with integrated hybrid

Applications

• Telephone Telemetry Systems
• Remote Utility Meter Reading
• Security Systems
• Industrial Control Systems
• Electronic Cash Terminals

Procurement Notes

Verify the specific package suffix against the datasheet to ensure correct physical dimensions and pinout compatibility. Confirm that the ordering suffix corresponds to the required reel or tube packaging format. Check RoHS compliance status and moisture sensitivity level ratings prior to assembly planning.

Selection Notes

Select this component when a multi-standard modem solution is required for voice-grade telephone lines. Ensure the host microcontroller supports the C-BUS serial interface protocol. Verify that the application environment falls within the specified operating voltage and temperature ranges.

Part Context

The CMX868AD2 belongs to the CMX868A family of communication semiconductors from CML Microcircuits. This series focuses on low-power modem solutions for legacy and specialized telecom applications. The AD2 suffix typically denotes a specific package variant, such as SOIC-24, distinct from other package options like TSSOP or DIP available in the same product family.

Replacement Considerations

Consult the official CML Microcircuits documentation for direct cross-reference part numbers. Evaluate alternative models within the CMX868A family if different packaging is required. Verify functional equivalence for all supported modem standards before substitution.

FAQ

What is the function of the Ring Detector circuit?

The Ring Detector identifies incoming ringing signals or line voltage reversals. It remains active during Powersave mode and can generate an interrupt to wake up the host microcontroller.

How does the device handle data synchronization?

The CMX868AD2 includes programmable Tx and Rx USARTs that meet V.14 requirements, supporting both asynchronous Start-Stop characters and synchronous 8-bit word transmission.

Can the device detect call progress signals?

Yes, the integrated tone detectors can be configured to identify standard call progress signals, 2100Hz answer tones, and user-programmed tone pairs.