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0.5w High Linearity Power Amplifier For Broadband Wireless (3.3 ~ 3.9 Ghz), Chin-Leong Lim
0.5w High Linearity Power Amplifier For Broadband Wireless (3.3 ~ 3.9 Ghz), Chin-Leong Lim
Chin-Leong Lim
This paper presents a 0.5 Watt amplifier that operates over the 3.3 ~ 3.9 GHz range. The target applications are pre-driver in base-stations and power amplifier in subscriber units. The design marries good Third Order Output Intercept Point (OIP3) and exceptional Power Added Efficiency (PAE) at IdB gain compression point (PldB). The performances are: -G = 11.8 dB, IRL & ORL < -8 dB, PldB = 28.5 dBm and OIP3 = 42.6 dBm. The superior performance is achieved through the use of Avago Technologies' proprietary 0.25um GaAs Enhancement mode pHEMT process. The device requires simple matching components to achieve wide bandwidth because of the built-in input pre-match. From the reliability standpoint, pHEMT devices are eminently suited to PA use -the drain to source resistance (RDSon) will inherently rise to counteract the thermal runaway that blights bipolar and HBT PAs. The internal bias circuit is temperature compensated and can be adjusted for either class A or class AB operation. The device is housed inside a standard 16 pin LPCC 3X3 package.
Tackle Wideband Rf Switching With Pin Diodes, Chin-Leong Lim
Tackle Wideband Rf Switching With Pin Diodes, Chin-Leong Lim
Chin-Leong Lim
PIN diodes make cheaper, faster and more reliable RF switches than the mechanical competition. The two methods of constructing PIN diodes, bulk and epitaxial, result in significantly different bias current, linearity and lower frequency limit. This paper compares the wideband series switching performances of a bulk PIN diode (w = 22.5 um, Tau = 300 ns) and an epitaxial diode (w = 6.5 um, Tau = 180 ns) in similar low-cost, miniature SOD-323 packages. Through simulation and experiment, we detected significant differences in insertion loss, isolation, and third-order intercept (IP3) performances between the two diode types. In conclusion, the design …