A SOI-BiCMOS RF-transmitter for personal digital cellular communication (PDC)

We present a 1-GHz RF-transmitter IC for Personal Digital Cellular Communications (PDC) application in Japan. This IC is mounted in a standard TQFP 32-pin package and it represents the first reported SOI-BiCMOS implementation for cellular usage. The IC utilizes a linear, fully-complex mixing of a UHF signal (650 MHz-750 MHz) and a fixed VHF signal (175 MHz or 250 MHz) to generate spurious-free, I-Q LO (850 MHz-1 GHz). The generated LO carrier is mixed with the /spl pi//4 DQPSK modulated baseband PDC signal in an I/Q upconverter/modulator. The I/Q upconversion signal path includes an upconversion I/Q modulator, a 2-stage linear 40 dB-AGC control circuit, an on-chip balun, and a +1 dBm output driver with on-chip double termination to 50 ohms. The transmitter has better than 50 dB LO-leakage suppression, sideband-rejection of 40 dB, and less than 65 dBc of spurious leakage at the output. The output noise floor is better than -139 dBc/Hz at 10 MHz offset from the carrier in full power mode. The IC dissipates 32 mA of maximum current from a 2.7 V supply.