Radio Eases 3G Handset Design

Exploiting a transmit-path architecture that eliminates the need for SAW filters, the latest Othello-3 CMOS RF transceiver promises to reduce W-CDMA mobile terminal board space by as much as 40%. The receiver section includes single-ended low-noise amplifiers for two high bands (1,710 MHz to 2,170 MHz) and one low band (824 MHz to 960 MHz). Driven by an on-chip fractional PLL synthesizer, direct down-converting quadrature mixers deliver baseband in-phase and quadrature signals to a variable-gain amplifier and programmable low-pass filter stages with dc-offset correction. The transmitter section includes a fractional PLL synthesizer, variable-gain amplifiers and quadrature modulators for high- and low-band outputs, as well as a root-mean-square RF power detector and d/a converter for power amplifier control. The Othello-3 (AD6551) is sampling now in a 6 mm x 6 mm, 40-lead lead-frame chip scale package. ANALOG DEVICES INC., Norwood, MA. (800) 426-2564.