A translinear-based chip for linear LINC transmitters

The LINC transmitter provides linear amplification using nonlinear but power efficient amplifiers. The signal component separator (SCS) is a crucial function of LINC. This paper presents a 200 MHz IF SCS chip implemented in a 0.8 /spl mu/m BiCMOS process using a novel design based on translinear circuits. The experimental LINC transmitter, built with the chip and nonlinear amplifiers, had output spurious levels around -55 dBc for both a NADC signal and a PHS signal. This implies a high degree of linearity.