Product description

The CMX991 is a single-chip, high performance, low cost RF quadrature transceiver that provides the core functions required to implement a full-featured radio transmitter and receiver.

It operates from 100MHz to 1GHz and its I/Q architecture supports multiple modulation types and bandwidths with a single radio design.

The half-duplex CMX991 integrates Tx modulators, Rx demodulators, IF PLL and IF VCO subsystems to minimise the external circuits needed when implementing a complete RF transceiver chip.

User-selected modes suit different application requirements.

The Tx path includes an I/Q modulator to accurately generate modulation at the IF frequency, which may then be translated to the final RF frequency by an integrated image-reject up-converter system.The I/Q modulator IF output is also made available for conversion to RF via external circuits, if desired.

The Rx path includes an integrated 1st Rx mixer having two outputs to support two external 1st IF filter choices, then an integrated 2:1 input MUX followed by VGA and wideband signal level measurement functions, to support AGC implementation.

The 1st IF signal is then either I/Q demodulated to Zero-IF or mixed to a Low IF output.

The CMX991 provides differential and single-ended Rx output options and differential amplifiers for flexible signal conditioning.

Read More

Devices are available through our distributors below:


  • SalesNetworkLogo_2
  • Mouser_logo
  • RFMW logo

Block diagram


Technical Portal

No additional information available.


  • High Performance (100MHz to 1GHz) RF Transceiver
  • Half-duplex Operation
  • Rx:
    – RF Mixer with Output Select
    – 1st IF Input Select
    – 1st IF Variable Gain Amplifier (VGA)
    – 1st IF Signal Level Indicator (SLI)
    – Two-mode Demodulator
    – I/Q Zero IF with Diferential Outputs
    – Selectable IF Outputs (450kHz or 455kHz)
  • Tx:
    – I/Q Modulator to IF
    – Image-reject Up-converter
    – IF and RF Outputs
  • IF:
    – IF LO Synthesiser
    – IF VCO Negative-Resistance Amplifier


  • Analogue, Digital and Multimode Radio
  • Software Defined Radio (SDR)
  • Portable, Mobile and Base Station Terminals
  • Data Telemetry Modems
  • ETSI:
    – EN 300 113, EN 301 166, EN 302 561,
    – EN 300 220, TS 102 361 (DMR)
  • APCO Project 25: Phase 1 and Phase 2 TDMA:
    – TIA-102.CAAB
  • Automatic Identification System (AIS) Transponders
  • Constant Envelope and Linear Modulation
  • Narrowband Systems: eg. 25kHz, 12.5kHz and 6.25kHz
  • Wideband Systems: eg. up to 2MHz
  • Satellite Communications

Power supply requirement

  • 3.3V

Not quite sure what you’re looking for?
We can tailor an existing product to your unique requirements

Design resources

EV9910B/EV9920B and CMX91 Questions

Q. What spurious response rejection can I expect from the EV9910B/EV9920B receiver?

A. The EV9910B/EV9920B has been tested for receiver spurious responses to EN300-113 with a 9600 baud GMSK modem.
The performance was limited only by the image rejection (approximately 30dB), other rejections being greater than the required 70dB.

The user may provide additional image filtering between the LNA and mixer input; this is detailed in the user manual.

CMX991 and CMX992 Operation Below 100MHz

This Application Note seeks to provide useful guidance on the use of the devices below 100MHz and contains details of how such operation can be demonstrated through component changes to the matching circuits on the EV9910B and EV9920B Evaluation Kits.

EV9910B/EV9920B - PDT* Configuration

Using the EV9910B and EV9920B to evaluate the CMX991 and CMX992 RF ICs for the Chinese *Police Digital Trunking (PDT) system.

EV9910B/EV9920B Evaluation Kit

EV9910B/EV9920B The EV9910B allows the evaluation of the CMX991 Quadrature/Low IF Transceiver. The CMX991 is an RF Transceiver IC providing I/Q modulator and up-conversion, superheterodyne receiver and IF local oscillator. EV9910_Product_Preview




C-BUS Guides

Guides to operation and interfacing

EV9910B Board Schematics

EV9910B high resolution schematics. Version D02

EV9910B Support Package

EV9910B Gerbers and BOM. Version D02

EV9910B Evaluation Software

EV9910B Evaluation Software. Requires a PE0003 Universal Interface Card. Version 5.1

PE0003 Driver

PE0003 USB driver for Windows. Version 1.0

Package: Q3

48-pin VQFN

VQFN Design Guidance Notes

VQFN Design Guidance Notes

Ask a question

Request a quote