An intermediate frequency (IF) variable gain amplifier (VGA) with exponential gain control for a radio receiver is fabricated in 0.25-µm CMOS technology. The techniques to improve the bandwidth and to reduce temperature dependence of gain are described. The complete VGA is composed of two stages of linearized transconductance VGA and three stages of fixed gain amplifier (FGA). The complete VGA provides a continuous 10 dB to 76.5 dB gain control range, an IIP3 of -11.5 dBm and an NF of 15 dB at 40 MHz.

A demodulator for short-range wireless interconnect using ASK/CDMA technique has been developed with 0.25 µm CMOS technology. The fabricated demodulator demonstrates the demodulation of 7.35 Mbps bit rate with 31 spread spectrum code length at 10 GHz carrier frequency.