A single-chip quad-band (850/900/1800/1900 MHz) direct conversion GSM/GPRS RF transceiver with integrated VCOs and fractional-n synthesizer

Recent trends in the integration of entire systems on-chip have spurred the development of homodyne radios as alternatives to the more mature yet harder to integrate superheterodyne architectures. This paper presents a monolithic device that integrates all of the functions necessary to implement a multiband homodyne global system for mobile telecommunications (GSM) radio except for the power amplifier (PA) and radio frequency (RF) passives. The single BiCMOS chip includes a quad-band direct conversion receiver that down converts RF to quadrature analog baseband. The front-end circuitry is followed by a low-DC-offset, high-dynamic-range, analog I/Q baseband chain. The transmit section is comprised of a quad-band up-conversion transmit phase-locked loop (PLL) including on chip transmit voltage-controlled oscillators (VCOs). The stringent GSM receive band phase noise specifications are met without the use of surface acoustic wave filters. A single ΣΔ fractional-N synthesizer locking a fully integrated ultrahigh frequency VCO generates the system local oscillator signal.