38 GHz driver and power amplifier MMICs in surface mount packages

The first pass design and performance of two driver and power amplifiers in SMD packages for 37-40 GHz radios is presented. Both circuits were designed and fabricated using 6-inch 0.15-μm GaAs PHEMT technology. While occupying a chip area of only 1.6 mm², the QFN 3×3 mm driver amplifier achieves a small signal gain of more than 21 dB over the 35- to 40 GHz frequency band. At 4 V and 250 mA bias, this packaged driver also has a P_1dB of +18.5 dBm, +21-dBm saturated output power, and +32 dBm OIP₃. To maximize the overall efficiency, the companion power amplifier has been co-designed with a custom air cavity 7×7 mm laminate package. At a bias point of 4 V and 1 A, this 4-stage packaged MMIC exhibits a small signal gain over 25 dB in the 37-40 GHz band, with a P_1dB > +28-dBm and +30-dBm saturated output power. Its linearity performance is also excellent with +38-dBm OIP₃. The PA also integrates an on-chip temperature compensated power detector, with a record dynamic range of more than 30 dB. For rugged and reliable operation, on-chip EOS and ESD protection is also discussed and implemented on these MMICs.