This paper presents a dual-mode multiband transceiver with DigRF interface implemented in a 0.13-μm CMOS technology. Based on direct conversion architecture, blocks in the transceiver can be configured to simultaneously support wavelength code-division multiple access (WCDMA) band I and four Global System for Mobile Communications (GSM) bands (PCS/DCS/GSM900/GSM850). In the receiver path, the narrowband radio-frequency front-end is comprised of multiple-gated low-noise amplifiers with capacitive desensitization and current-mode passive mixers with the proposed second-order input intercept point (IIP2) calibration to comply for surface-acoustic-wave-less application. In the transmitter path, a high-linearity mixer and parallel Class-AB PA driver are adopted. Low-noise wideband frequency synthesizers with adaptive frequency calibration are proposed to cover all modes and bands. This reconfigurable transceiver achieves -5.6/-2/-6 dBm in-band third-order intercept point for WCDMA/GSM HB/GSM LB respectively, and >;65 dBm IIP2. At the maximum output power, the transmitter achieves 2.3% rms error vector magnitude for WCDMA I and 1.67° phase error for a GSM system.