Digital transmitter delivers software-defined radio benefits to macro- and small cell base stations

June 11, 2012 // By Paul Buckley
Maxim Integrated Products, Inc. has introduced the MAX5879 multi-Nyquist RF digital-to-analog converter (RF DAC) that delivers a fully digital software-defined radio (SDR) transmitter, enabling a common hardware platform for multicarrier, multiband, and multistandard base stations.

Working with FPGA-based direct digital synthesis (DDS), the MAX5879 RF DAC architecture shifts the functions of the analog quadrature modulator and agile local oscillator (LO) used in current architectures into the digital domain. This eliminates in-phase and quadrature errors, and LO feedthrough, commonly associated with analog upconversion. The MAX5879 simplifies RF design and improves reliability for base-station transmitters.

The MAX5879’s selectable frequency response modes support direct RF synthesis of common 3G/4G cellular bands in multiple Nyquist zones from 700 MHz to 2.8 GHz. A single MAX5879 RF DAC serves multiple standards such as multicarrier GSM, WCDMA and LTE without compromising dynamic performance. This allows designers to use a common hardware platform that cuts development time-to-market.

Smartphones and tablet computers demand more bandwidth from wireless base stations. A MAX5879 RF DAC-enabled transmitter delivers much wider bandwidths than traditional architectures.

The MAX5879’s selectable 4:1 and 2:1 input data multiplexer lets hardware designers reduce input word rates, and this allows use of lower-cost FPGAs.

MAX5879 RF-DAC technology is also ideal for microwave radio links used in mobile backhaul equipment; for CMTS/edge-QAM boxes used in cable head-end equipment; and for other wideband communication systems.


The device operates across the -40°C to +85°C range and is packaged in a 256-ball (17 mm x 17 mm) CSBGA.

MAX5879 RF-DAC is fully released and in production.

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