1.9 GHZ SI DIRECT CONVERSION RECEIVER IC FOR QPSK MODULATION SYSTEMS

A 1.9 GHz direct conversion receiver (DCR) chip which integrates an LN A, I/Q mixers (MIX), active lowpass filters (LPF) and variable gain am plifiers (VGA), was fabricated. Because the DCR for QPSK modulation sy stems is sensitive to the 2nd-order nonlinearity, linearization techni ques are adopted in MIX and LPF. The DCR chip was fabricated using a B iC-MOS process, and the die size is 5.1 mm by 5.1 mm. The chip can ope rate from 2.7 V supply voltage and consumes 165 mW when all the functi ons are activated. Suppression of local signal radiation and the 2nd-o rder distortion indicate the feasibility of Si-based DCR for QPSK modu lation systems such as PHS.