标签: tc1142

RF bandwidths for cellular systems such as AMPS, TACS, GSM,TDMA, and CDMA range from 800MHz to 1.0GHz. To provide RFtransmissions over this range of frequencies, Gallium Arsenide(GaAs) has become the technology of choice and offers severaladvantages over silicon technology: a much higher cutoff fre-quency, higher breakdown voltage, lower noise figure, and higherpower-added efficiency. This translates to lower power dissipationand longer talk time for cellular subscribers.AN808UsingtheTC1142forBiasingaGaAsPowerAmplifierAPPLICATIONCIRCUITAuthor:PatrickMaresca,MicrochipTechnology,Inc.Figure1showsatypicalapplicationcircuitforbiasingaGaAsPAinacellularsubscriberunit’stransmitter.Eachkeycomponentofthecircuitisdescribedbelow.INTRODUCTIONRFbandwidthsforcellularsystemssuchasAMPS,TACS,GSM,……