This paper describes a low-power-consumption direct-conversion CMOS transceiver for WLAN systems operating at 4.9-5.95 GHz. Its power consumption is reduced by using a resonator-switching wide-dynamic-range LNA. The broad tuning range needed for multiple-channel-bandwidth systems is provided by a single widely tunable low-pass filter based on negative-source-degeneration-resistor transconductors, and its automatic frequency-band-selection PLL supports multiple standard 5-GHz WLAN systems. The system noise figure is 4.4 dB at a maximum gain of 74 dB, and the receiver IIP3 is +5 dBm and 21 dBm for the minimum and maximum gain modes, respectively. The error vector magnitude (EVM) of the transmitted signal is 2.6%. The current consumption is extremely low, 65 mA in the transmitter path and 60 mA in the receiver path.Index Terms-CMOS transceiver, frequency synthesizer, HiperLAN/2, HiSWANa, IEEE 802.11a, low-noise amplifier (LNA), low-pass filter (LPF), orthogonal frequency division multiplexing (OFDM), wireless LAN (WLAN).
A new technology of fabricating 0.25 pm gate E Dheterojunction FET LSIs is developed as a step towards the development of ultra low supply voltage LSIs. This technology, which is based upon all dry-process techniques, includes the formation of a 0.25 pm gate opening through the use of optical lithography and inner Si02 sidewalls. The fmax and the gmmax for a Y-shaped gate E-HJFET are 108 GHz and 520 mS/mm, respectively. Excellent performances are obtained with DCFL ring oscillators using n-AlGaAs/i-InGaAs pseudomorphic E/D-HJFETs. These include 18 ps/G unloaded delay and 109 ps/G loaded delay (FI=FO=3, L=lmm) with 0.15 mW/G at a low supply voltage of 0.6 V, where inverters have a sufficient noise margin of more than 180 mV. Also, 10 Gbps error-free operation of a selector switch is demonstrated with 9.4 mW at 0.6 V.
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