A 900MHz/1.9GHz integrated transceiver and synthesizer IC for GSM

An integrated GSM compliant 2.7V, 900MHz/1.9GHz dual band transceiver with an I and Q interface including a dual integer N synthesizer is presented. The receiver provides a total of 110dB of gain range with 80dB of programmable gain range at IF selectable in steps of 2dB and 30dB of programmable gain range in the baseband selectable in steps of 10dB. An on-chip track and hold based DC offset correction scheme is provided to remove DC offsets before each receive slot in a GSM application. An on chip VHF oscillator achieves a phase noise level of -106dBc/Hz at 100kHz offset when operating at 800MHz and the synthesizer provides a close-in phase noise performance of better than -78dBc/Hz at 1kHz offset. The frequency translation loop based transmit section achieves an unwanted sideband suppression of -40dBc, LO leakage of -42dBc, and third order spurious rejection of -69dBc. The transmit output noise level is -165dBc/Hz at a 20MHz offset from the carrier.