A low-power and variable-gain transceiver front-end chip for 5-GHz-band WLAN applications

A low-power 5-GHz-band transceiver front-end chip is described that uses highly reliable, high-performance InGaP/GaAs HBTs and complies with IEEE802.11a standards. Integrated into the chip (2.4/spl times/2.4 mm/sup 2/) are a 20/0-dB dual-gain low-noise amplifier and a wide IF-range down-conversion mixer in the receiver path, a 20-dB variable-gain driver amplifier and a low and stable local oscillator (LO) leakage up-conversion mixer in the transmitter path, and a high-isolation LO buffer. Very low power consumption (120 mW) is attained with a single 3-V supply voltage in receiver mode together with high transceiver performance. The key features and new circuit approaches in each function block are described in details. Measurement showed that a 5-GHz OFDM-modulated Tx signal meets IEEE802.11a standards.