A direct-conversion receiver for 900 MHz (ISM band) spread-spectrum digital cordless telephone

A single chip direct-conversion receiver for use in the 900 MHz ISM (industrial-scientific-medical) band has been fabricated in a 25 GHz f(T) silicon-bipolar process, The receiver has a maximum gain of 105 dB with more than 80 dB of gain-control range, Integrated quadrature mixers and phase-shift networks are included, The typical phase error of the I/Q outputs is less than 1 degree, A class-AB servo amplifier is used to reduce de offset while maintaining a turn-on time of 200 mu s. An integrated filter is included to improve channel selectivity, The integrated circuit operates on a supply voltage range of 2.7 to 5.0 V and draws 50 mA of supply current.