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).
MAX2395 Output Matching to a SAW Filter for Optimum Cascaded Gain Flatness http://www.maxim-ic.com/app-notes/index.mvp/id/3040