Analog baseband for WCDMA implementation by using digital-controlled DC Offset Cancellation

An analog baseband for Wideband Code-Division Multiple-Access (W-CDMA) direct-conversion receiver is presented. The baseband achieves 39dB gain with 3dB/step step and 2.1MHz cut-off frequency of <;0.5dB passband ripple. The DC offset caused by LO self-mixing and I/Q mismatch are cancelled by compensation DACs in every PGA stage and the remaining output DC offset voltage is within ±5mV. The DAC-based DCOC consumes only 150uA current and occupies only 0.003mm² chip area. The design was implemented in 0.13um CMOS technology with chip area of 1.92mm² (with I/Q two paths), the analog baseband achieves in-channel OIP3 of 25.5dBm and consumes 26mA of one path with on chip ADC buffers under 1.2V power supply.