A novel power amplifier module for quad-band wireless handset applications

This paper presents a novel power amplifier module (PAM) designed for GSM850MHz, GSM900MHz, DCS1800MHz and PCS1900MHz handset applications. The module combines an InGaP HBT GSM/DCS/PCS power amplifier IC, two integrated couplers, a dual-band logarithmic RF power detector/controller and some additional passive components. The logarithmic RF power detector was implemented in the module to accomplish linear-in-dB output power dependency. The module features closed loop automatic power control, fully integrated impedance matching at input and output ports with DC blocks and plastic encapsulated on a 10mm×10mm GTek substrate. The module offers higher accuracy of output power (Pout) control, smaller size, lower bill-of-materials and a shorter Pout calibration time to handset manufacturers. Compared with other conventional power amplifier modules in the market, due to higher accuracy our novel design significantly reduces the power consumption during normal operation. It is a very desirable RF PAM to handset designers because of its unique features. Our design makes it possible for the handset manufacturers to calibrate Pout at one or two points, with error as low as +/-0.3dB, thus reducing test time in mass production. Under a low single supply voltage of 3.2V, the PAM provides 35dBm output power, 55% PAE in GSM900 band and 33dBm and 50% PAE in DCS1800 band.