Application of enhancement mode FET technology for wirelesssubscriber transmit/receive circuits

摘要

Single-supply power amplifiers have become the new paradigm innportable phone handsets due to the recent availability of heterojunctionnbipolar transistor (HBT) and pseudo enhancement mode PHEMT technology.nWe have developed a true enhancement mode heterostructure insulated-gatenFET device (HIGFET) which is suitable for use in both saturated andnlinear power amplifiers. A three-stage power amplifier designed forn1900-MHz NADC application delivered +30-dBm output power and 41.7%npower-added efficiency with an adjacent channel power of -29.8 dBc andnalternate adjacent channel power of -48.4 dBc. In addition to this, wenhave demonstrated excellent noise figure and linearity performance fornsmall-signal applications. At 900 MHz and bias conditionsnVDS=1.0 V and IDSQ=1 mA, a single-stage amplifiernachieved a noise figure of 1.17 dB with an associated gain of 18.5 dB.nThese results make the technology an ideal candidate for application innboth transmitter and receiver circuits