A 28-nm CMOS 76−81-GHz power amplifier for Automotive radar applications

A 28-nm 3-stage single-ended CMOS 76−81-GHz power amplifier (PA) is presented to meet the extended temperature range of 125 °C and quality requirement for Automotive radar sensors. The proposed PA has single-ended input and output ports to minimize pin count, current consumption, die size and remove the need for off or on chip baluns. The three stages are implemented as common-source stages. A combination of Coplanar waveguide (CPW) and inductors are used for impedance matching and impedance transformation purposes for best compromise between the conflicting products die size and performance requirements. At 125 °C ambient temperature, the PA achieves linear power gain of 17 dB, with saturated output power of 12 dBm and output 1-dB compression point of 7.5 dBm, and peak PAE of over 13%, translating to less than 100 mW of power drain. The output power varies by less than 2 dB across the combined frequency band of 76–81 GHz and ambient temperature range of 25 °C to 125 °C. The PA occupies a die area of 590 µm × 300 µm. To the best of the authors' knowledge, the developed PA shows the best output power, PAE and die size performance, with best frequency and temperature stability for extended temperature range of 125 °C among 76–81-GHz CMOS automotive PA's reported to date, achieving performances so far seen from high-end SiGe PA's, yet with much lower power consumption.