CMX868AD2-TR1K

Overview

The CMX868AD2-TR1K 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 an integrated DTMF encoder/decoder, programmable Tx/Rx USARTs compliant with V.14, flexible line driver/receive hybrid circuits, a hook switch relay drive output, and a ring detector. Control and data transfer are managed via a high-speed serial C-BUS interface compatible with most microcontrollers.

Feature Summary

• Multi-standard modem capability supporting V.22 bis, V.22, Bell 212A, V.23, Bell 202, and V.21/Bell 103 protocols.
• Integrated DTMF/Tone generator and decoder with user-programmable tone detection capabilities.
• Flexible transmit and receive USARTs meeting V.14 requirements for asynchronous and synchronous data handling.
• On-chip programmable line driver and receive hybrid circuits requiring only passive external components for 2-wire or 4-wire interfaces.
• Dedicated Ring Detector circuit that functions in Powersave mode to wake up the host microcontroller upon line voltage reversal or ringing.

Applications

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

Procurement Notes

Verify the specific package variant required, as the base model CMX868A is available in TSSOP, SOIC, and DIP packages. Confirm the suffix 'TR1K' indicates tape and reel packaging containing 1000 units per reel, distinct from tube packaging options. Ensure the design accounts for the component's moisture sensitivity level and reflow soldering profile appropriate for surface-mount assembly.

Selection Notes

Select this component when a multi-standard analog modem solution is needed for voice-grade telephone lines. It is suitable for applications requiring simultaneous support for various FSK, DPSK, and QAM modulation schemes within a single IC. Consider the integrated DTMF capabilities and low-power standby mode if battery operation or energy efficiency is a priority for the end product.

Part Context

The CMX868AD2-TR1K belongs to the CMX868A family of low-power V.22 bis modems from CML Microcircuits. This family is engineered for robust performance in noisy telephone environments. The AD2 suffix typically denotes a specific package type and temperature grade, while the TR1K suffix specifies the reel quantity for automated manufacturing processes.

Replacement Considerations

Direct replacements within the same family include other variants of the CMX868A series differing primarily in package style (e.g., CMX868AE2 for TSSOP) rather than functional changes. Verify pin compatibility and thermal characteristics when substituting between different package types such as SOIC versus TSSOP.

FAQ

How does the CMX868AD2 handle data transmission formats?

The device includes programmable Tx and Rx USARTs that meet V.14 requirements. They can be configured to transmit and receive asynchronous Start-Stop characters or synchronous 8-bit words, allowing flexibility for unformatted data handling.

What is the function of the Powersave mode?

Powersave mode disables most internal circuitry to reduce power consumption. However, the C-BUS interface and the Ring Detector remain active, allowing the device to detect incoming calls or line voltage reversals and generate an interrupt to wake up the host microcontroller.

Can the DTMF blocks be used for non-standard signals?

Yes. In addition to standard DTMF encoding and decoding, the DTMF/Tone Generator and Detectors can be programmed to transmit and detect user-specific single or dual-tone signals, call progress signals, or modem calling and answering tones.