A 65nm CMOS low-noise direct-conversion transmitter with carrier leakage calibration for low-band EDGE application

A low-noise EDGE transmitter implemented in a 65nm CMOS process using direct-conversion architecture for low-band application is presented. The transmitter consists of a programmable-gain I/Q modulator, a frequency divider and a power detector for carrier leakage calibration. The design delivers maximum output power > 1.5 dBm with a 0.5 dB gain step for the 30 dB dynamic range and has < -68 dBc modulation spectrum at 400-kHz offset under maximum gain level. The out-of-band noise at 20 MHz offset with the power amplifier is -80.9 dBm with 100-kHz resolution bandwidth. The carrier leakage suppression after calibration can reach -50 dBc. The design consumes 21 mA at 1.5-V supply and 40 mA at 2.7-V supply and is housed in a 40-pin QFN package.