A Single Chip 802.11abgn Enhancement Mode PHEMT MMIC with dual LNAs, Switches, and Distortion Compensation Power Amplifiers

Abstract

An enhancement mode PHEMT MMIC with integrated dual low noise amplifiers, dual switches, and dual distortion compensation power amplifiers is presented. It is used in an 802.11abgn FEM (Front End Module) which further integrates the antenna diplexer, LNA post filters, PA pre-filters, and baluns. The LNAs provide less than 1.2dB noise figure in the 2.4/5-6GHz receive chains at 16dB gain and 10mA. The switches can handle up to 30dBm peak power with less than 1.4dB loss and with 25dB isolation. The power amplifier section provides fully matched 26dB gain with 25dBm of saturated power. In the 802.11g 2.4GHz transmit mode the MMIC gives over 20dBm linear power out under 54Mbps OFDM, at 4% EVM, while drawing only 123mA of peak current. In the 802.11a 5-6 GHz transmit mode the MMIC gives over 20dBm linear power out under 54 Mbps OFDM, at 6% EVM while drawing 149mA of peak current. The MMIC has integrated all control functions for power down and mode select; while the power amplifiers have integrated directional couplers and temperature compensated power detection. This is the highest integration and performance level combination known to be published for 802.11abgn application specific integrated circuits.

Noise characteristics of dual-gate AlGaAs/InGaAs pHEMTs

“…The excellent RF performance has also manifested by dualgate D-mode FET and its performance is similar to cascode structure [6], [7]. This implicates that the cascode structure can be replaced by dual-gate structure to obtain the similar noise performance but reducing chip size.…”

Nanometer-scale InGaAs field-effect transistors for THz and CMOS technologies

“…Commercial processes that integrate Enhancement-Mode and Depletion-Mode InGaAs PHEMTs as well as InGaAs Bipolar Transistors are available today in foundry basis [8]. These processes enable highly integrated mixed-signal sub-systems such as single-chip WLAN MMICs [9].…”

2.4GHz WLAN D-pHEMT LNA

“…Several designs have been reported for WLAN applications using GaAs pHEMT, MESFET, and HBT technologies, especially, HEMT devices are the best candidates for LNAs because they have excellent noise property and associated gain, compared to other devices [3][4][5][6].Up to the present the best data reported was a two-stage pHEMT MMIC LNA which had a minimum noise figure of 0.76dB and an associated gain of 16dB at 5GHz [7]. In this paper, it is demonstrated with a fully monolithic LNA using depletion mode pHEMT technology achieving a noise figure of 0.93dB at 2.4GHz with an associated gain more than 20dB.The LNA provide low noise and high gain performance while offering the benefit of integration.…”