A 2.4GHz 2Mb/s versatile PLL-based transmitter using digital pre-emphasis and auto calibration in 0.18µm CMOS for WPAN

A fully integrated 2.4GHz 2Mb/s transmitter which is part of a highly integrated WPAN RF transceiver SoC using a 0.18 mum RF CMOS 1P6M process is presented. The transmitter uses a DeltaSigma fractional-N PLL architecture. It transmits 2 Mb/s GFSK and GMSK modulated signals and is compliant with the IEEE802.15.4 and Bluetooth 1.2 standards. The transmitter consumes 18 mA at 3 dBm output power and occupies 1.1 mm². The transmitter does not use any quantisation noise cancellation techniques leading to 60% die area and 50% power consumption savings, yet meets the FCC emission regulations in restricted bands with 12 dB margin. It uses a novel calibration system that maintains a worst-case RMS phase error of 8.4deg for 2 Mb/s GMSK in the presence of plusmn50% variation in the PLL closed-loop bandwidth (CLBW). The calibration system consumes 0.4 mA for a period of 66 mus, which is significantly less power-consuming than a recently reported scheme.