CMX998

Cartesian Feed-back Loop Transmitter

Quantity Price Guide: $11.81
Features
  • Frequency Range: 100MHz to 1GHz
  • Wide-Band Noise: -148dBc/Hz
  • C-BUS (SPI Compatible) Serial Interface
  • Gain Control
  • Error Amplifier
  • Up-Converter Forward Path
  • Down-Converter for Feedback Linearization
  • 360o Loop Phase Shift Control
  • DC Offset Measurement Output
  • Open-Loop Function
  • Instability Detector
  • Linearization Gains of 30dB or more Achievable
  • Flexible Digital Interface
Applications
  • TETRA Terminals

  • TETRA 2 Terminals

  • APCO P25 Phase 2

  • Software Defined Radio (SDR)

  • Aviation Systems

  • Mobile Satellite Terminals

  • Linear Modulation Schemes:
    QPSK, pi/4 DQPSK, 8PSK, QAM, OFDM, F4FM
  • Direct Interface to CMX981 and CMX980A Digital-Radio Processor ICs

Package Styles:
CMX998Q1

Supply Requirement:
3.0V to 3.6V power supply
Description
A Cartesian Loop improves the efficiency and linearity of transmitters for non-constant envelope modulation systems.
The CMX998 is an integrated solution for a Cartesian Feedback Loop based linear transmitter.

Acting as a direct conversion quadrature mixer from I and Q to RF output, it provides the capability to linearize the Power Amplifier (PA) via feedback from the PA's output.
Included are forward and feedback paths; local oscillator circuitry including loop phase control; an instability detector and uncommitted op-amps for input signal conditioning.

The device operates from a single 3.3V supply over a temperature range of -40°C to +85°C and is available in a 64-no leads VQFN (Q1) package.

Click for Block Diagram