| Power amplifier (PA) is the key block of the wireless communication transmitter in RF, whose function mainly determines the cost, the power and the size of the transceiver. In order to meet the requirements of low cost, low power and small size, RF transceiver needs a CMOS power amplifier.With the development and application of the third wireless communication standards, multi-band and multi-mode application requirements are brought to RF IC design as well as the power amplifier of transceiver. Through the analysis of systematic structure and the basic theory of power amplifier, a concurrent multi-band power amplifier is presented according to the mobile communication standards, GSM0.9GHz and PCS1.9GHz.Firstly, the basic charecteristic of power amplifier, non-linear effects of devices and RLC network are introduced and discussed. Then the limitations of the CMOS process for power amplifiers are proposed,and they will be used as the instructions of the design of power amplifer.Secondly, the theory of concurrent power amplifier is studied and discussed in details as well as analysis and optimation of multi-band input and output match. Owing to the low breakdown voltage and limited transconductonce amplification ability of the CMOS process, the design of the single-ended three-stage topology is proposed. Besides in the application of bias circuits, a reference of high pricision and high power supply rejection (PSR) is presented which can also be used in low voltage supply application.Finally, based on TSMC 0.35μm RFCMOS process, the multi-band power amplifer is simulated by Cadecce tool. The simulation results show that, the 1dB compression point is above 22dBm, the output power is 23dBm, the power gain is 23dB, and the peak power added efficiency (PAE) is 30%. |
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