A direct conversion multi-band CDMA transmitter with single common resistive RF modulator and LO generation

A highly integrated multi-frequency CDMA transmitter using a simplified architecture based on a single common RF modulator and LO generation is presented. This chip up converts directly the I/Q base band signal to RF in two stages and delivers the RF signal to the power amplifier. The chip provides more than 80dB power control range in both bands and it is designed to deliver +5.5dBm in CDMA mode in cellular band and +7dBm in CDMA mode in PCS band at 70 mA and 79 mA respectively at nominal supply and temperature. It also provides -51 dBc and -57 dBc ACPR for the low and high bands. The chip was implemented using the Philips 0.25 mum BICMOS Qubic4+ process