CMX909BE2

Overview

The CMX909BE2 is a half-duplex GMSK packet data modem manufactured by CML Microcircuits. It supports data rates up to 38.4 kbits/sec and operates on 3.0V or 5.0V supplies. The device features an 8-bit parallel host processor interface, on-chip packet detection, and full/short data packet framing. It includes Mobitex compatibility with R14N short block frames, flexible operating modes, and power-saving options. The component is housed in a 24-pin TSSOP package.

Feature Summary

• GMSK modulation and demodulation with decision feedback equalization
• On-chip packet handling including CRC, FEC, interleaving, and scrambling
• Parallel host processor interface for direct microcontroller connection
• Mobitex compatible with support for R14N short block frames

Applications

• Mobitex terminals
• Wireless telemetry systems
• License-free radio data applications
• ISM band radio schemes

Procurement Notes

Verify the specific ordering suffix 'E2' corresponds to the 24-pin TSSOP low-height package variant as documented in the official datasheet. Confirm that the required external components, such as decoupling capacitors and crystal oscillators, are sourced separately according to the recommended schematic values. Ensure the host system provides the necessary 3.0V or 5.0V supply rails.

Selection Notes

Select this model when a half-duplex GMSK modem with integrated packet processing is required. It is suitable for designs needing Mobitex compliance and reduced host CPU load through hardware-based frame formatting. Consider the 24-pin TSSOP package constraints for PCB layout. Verify compatibility with existing FX909A or MX909A designs if backward compatibility is a priority.

Part Context

The CMX909BE2 belongs to the CMX909B series of GMSK packet data modems. It is pin, function, and software backwards compatible with the FX909A and MX909A modems, allowing for potential drop-in replacements in legacy designs while offering improved performance and lower voltage operation capabilities.

Replacement Considerations

The CMX909BD5 (SSOP-24) and CMX909BP4 (TSSOP-24) are alternative package variants within the same functional family. They share identical electrical characteristics and pinouts but differ in physical housing dimensions.