WCDMA Quasi-Direct Modulator with VGA and PA Driver

The MAX2395 fully monolithic quasi-direct modulator IC is designed for use in WCDMA/UMTS transmitters. The quasi-direct modulation architecture reduces system cost, component count, and board space compared to transmitters using an IF SAW filter with IF VCO and IF synthesizer blocks.

The MAX2395 includes I/Q baseband filters, an IF I/Q modulator with VGA, a fully monolithic VCO with PLL, an upconverter mixer, an RF VGA, and a power amplifier (PA) driver. The use of the quasi-direct modulator scheme ensures 5% (typ) EVM and a 30dB (min) carrier suppression. The RF VGA and IF VGA provide a nominal 90dB of output power control. No external local oscillators are required, enabling efficient implementation of variable duplex offset systems.

The PLL is programmed by loading data on the SPI™/MICROWIRE™-compatible 3-wire serial bus. The IC operates from a single +2.7V to +3.3V supply. The devices are available in space-saving 28-pin QFN and thin QFN exposed-pad packages (5mm x 5mm).

Applications

* UMTS/EDGE Phones * W-TDD Phones * WCDMA Phones

* 5% EVM for POUT = +6dBm

* 1920MHz to 1980MHz Operation

* +2.7V to +3.3V Single-Supply Operation

* +6dBm Output Power at 72mA

* 81dB Minimum Automatic Gain-Control (AGC) Range

* Automatic ICC Throttle Back for Optimal Power Consumption

* No IF SAW Filter Necessary

* On-Chip RF PLL, with Fully Monolithic VCO

* Ultra-Low External Component Count