Product description

The CMX994, CMX994A ,CMX994E, CMX994G is a family of direct conversion receiver ICs with PowerTrade™; the ability to dynamically select power against performance modes to optimise operating trade-offs.

CMX994 – Standard and low power modes
CMX994A – Standard and additional low power modes
CMX994E – Enhanced, standard and low power modes
CMX994G – Enhanced, standard and low power modes, 30MHz guaranteed performance

The CMX994/A/E/G offer exceptional blocking performance, typical values are in the range 98dB to 102dB depending on the measurement method. All three devices include a broadband LNA with gain control followed by a high dynamic range, very high IIP2, I/Q demodulator. The receiver baseband section includes amplifiers and precise, configurable bandwidth, baseband filter stages. LO generation is provided by an integer-N PLL and a VCO negative resistance amplifier; an external LO may also be used. LO dividers are provided for flexible multi-band operation.

The CMX994/A/E/G operates from a single 3.3V supply over a temperature range of –40°C to +85°C and are available in a small 40-pin VQFN (Q4) package.

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  • Direct Conversion Receiver Family with PowerTrade™ Flexible Power vs. Performance Modes – CMX994 – Standard and Low Power Modes – CMX994A – Standard and Additional Low Power Modes – CMX994E – Enhanced, Standard and Low Power Modes – CMX994G – Enhanced, Standard and Low Power Modes, 30MHz guaranteed performance for radios operating down to 30MH
  • Rx Single Conversion to Zero IF, Near-zero IF or Low IF; Zero IF Eliminates Image Responses
  • Very High Mixer IIP2 for Practical Zero IF Receiver
  • 100MHz to 1000MHz I/Q Demodulator (CMX994A/E/G) 100MHz to 940MHz I/Q Demodulator (CMX994) Extended Operation down to 50MHz or 30MHz (CMX994G)
  • LNA with Gain Control
  • Precise Filtering with 1:2:4 Bandwidth Select Control
  • Mixer Bandwidth up to 20MHz
  • Local Oscillator – LO synthesiser – VCO Negative Resistance Amplifier – Rx LO Divide by 2, 4 or 6 Modes – Tx LO Output with Divide by 1, 2, 4 or 6 Modes
  • Small Size 40-pin VQFN Package


  • Analogue/digital Multi-mode Radio
  • Software Defined Radio (SDR)
  • Data Telemetry Modems
  • Satellite Communications
  • Constant Envelope and Linear Modulation
  • Rx Function Compatible with CMX998
  • Cartesian Feedback Loop Transmitter
  • Narrowband e.g.: 25kHz, 12.5kHz and 6.25kHz
  • Wideband Data e.g. >1MHz Bandwidth

Power supply requirement

  • 3.0 to 3.6 V

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Design resources


Q, Are the CMX994A, CMX994E AND CMX994G devices pin compatible with the CMX994 in my digital radio? A, Yes all four devices are pin and function compatible.  However if the CMX994A, CMX994E or CMX994G are used in an existing CMX994 design, it is recommended that the new extended DC Offset register is used.

There are additional benefits in adopting the CMX994A, CMX994E and CMX994G including additional low power operating modes, enhanced mixer IM capability and guaranteed 30MHz operation, these are illustrated below:

Frequency Estimation for a VCO using a Negative Resistance Amplifier

Application Note describing how to estimate the operating frequency of VCO designs using a negative resistance amplifier. An Excel spreadsheet that automates the calculation is available below.

Excel Spreadsheet - Frequency Estimation for a VCO using a Negative Resistance Amplifier

An Excel spreadsheet that calculates the operating frequency of VCO designs using a negative resistance amplifier. An Application Note describing the process is available above.

CMX994/A/E Interference Immunity

Through clarification of blocking and second order intermodulation performance, together with empirical measurement, this app note illustrates the excellent characteristics of the CMX994/CMX99A/CMX994E marking its suitability for professional radio designs.

CMX994A / CMX994E 400MHz to 470MHz Operation

An Application Note demonstrating through the use of a simple RF matching circuit for the CMX994A and CMX994E devices in 400MHz to 470MHz band applications. Comparative measurements are made with the existing EV9942A/E and DE9945A Evaluation Boards throughout and results provided.

CMX994/A/E LNA Performance and Applications

An application note that describes the performance characteristics of the CMX994’s LNA and the benefits of this device for typical PMR radio designs.

CMX994 - Demonstration Video Scripts

These scripts are used in the "CMX994 Demonstration" video. The scripts guide the user through Tx/Rx frequency trimming, Rx I/Q DC offset calibration, Rx Equalizer training, Tx I/Q DC offset calibration, and formatted data transfer.

DE9941 DE9941 The DE9941 is a small demonstration platform for the CMX994 Direct Conversion Receiver, the CMX998 Cartesian Loop Transmitter and the CMX7164 Multi-mode Wireless Data Modem. DE9941_Product_Preview


EV9942A/9942E EV9924E board Two versions of the Evaluation Kit are available allowing the user to investigate all aspects of the chosen CMX994, high-performance direct conversion receiver. A common PC-based application identifies the CMX994 version and starts an interactive GUI for configuration and control. A separate hi-res schematic is available for both versions of the EV9942. EV9942_Product_Preview

EV9942 User_Manual

C-BUS Guides

Guides to operation and interfacing

EV9942 Evaluation Software

A common GUI-based application for the EV9942/EV9942A/EV9942E Evaluation Kits. A PE0003 Universal Interface Card is required to use this application. Version 4.1

EV9942 Quick Start

A simple guide to help users get started evaluating the EV9942, EV9942A and EV9942E Evaluation Kits. Ver.2

EV9942A Board Schematics

EV9942A Board high-resolution schematic. Ver.A03

EV9942E Board Schematics

EV9942E Board high-resolution schematic. Ver.A02

PE0003 Driver

PE0003 USB driver for Windows. Version 1.0


EV9942A Board BOM Ver.A03


EV9942A Board BOM Ver.A02

Package: Q4

40-pin VQFN

VQFN Design Guidance Notes

VQFN Design Guidance Notes

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