Fully Integrated Multi-Band W-CDMA Transmitter with Minimum Carrier Leakage and Optimized Power Consumption Mode

A fully integrated multi-band, 0.25 mum BiCMOS direct-conversion transmitter for wide-band code division multiple access (WCDMA) is described. A new approach based on a cascaded attenuator and amplifiers creates the full necessary power range in RF and successfully suppresses the carrier leakage without any calibration needs. The transmitter uses also an optimized power control feature that allows current saving while meeting linearity requirements. The chip provides more than 85 dB power control range in both bands and it is designed to deliver +7 dBm in at 800-900 MHz and +5 dBm at 1700-1900 MHz with 70 mA and 79 mA respectively at nominal supply and temperature. It also provides an error vector magnitude (EVM) of 2.5% and an adjacent channel leakage ratio (ACLR) of -53 dBc in high band and 4.4% EVM with -48 dBc ACLR in low band