A CMOS millimeter-wave (mmWave) downconversion mixer with a local-oscillator (LO) buffer is proposed for wireless Gb/s data-transfer enabling systems, such as 5G systems. To obtain high linearity at low supply voltages, the proposed mmWave downconversion mixer adopts an on-chip transformer-based topology. In order to achieve differential to single-ended conversion and IF output matching, while maintaining a high linearity performance, the proposed mmWave downconversion mixer incorporates an active balun with common-source and common-drain configurations employing common-mode noise and third-order intermodulation distortion cancellations. The proposed downconversion mixer with active balun and LO buffer was implemented using a 65-nm CMOS process and it draws 18 mA from a 1 V supply voltage. It demonstrates a gain greater than 5.6 dB, noise figure less than 10.9 dB, and third-order output intercept point more than 12.4 dBm, in the band from 57 to 66 GHz.

A short-circuit detection (SCD) circuit is proposed for power electronics systems that use silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs). The proposed SCD circuit incorporates a digital circuit for processing the voltage induced at the parasitic inductance of the source of SiC MOSFET to obtain an improved stable turn-off operation of the SiC MOSFET under SC condition. Compared with that of the conventional analog signal processing based SCD circuits, the proposed circuit has the advantages of having a turn-off operation which is robust to process, voltage, and temperature variations, being fully integrated without the use of external components and ease of design. The proposed circuit was implemented in a 350-nm Bipolar-CMOS-DMOS process. For functional verification, an SC test board integrating the proposed SCD circuit was developed. Experimental result validates that the proposed SCD circuit effectively functions under SC condition.

A low noise and highly linear wideband CMOS receiver front-end for digital TV receivers is proposed. The proposed RF front-end comprises a wideband noise canceling common gate low noise amplifier (LNA) with a capacitively cross-coupled current source, a highly linear up-conversion micromixer with third-order intermodulation distortion cancellation, and a highly linear surface acoustic wave (SAW) driver with enhanced loop gain. The RF front-end was fabricated using a 0.13 μm CMOS process and it draws 27 mA from a 1.5 V supply voltage. It achieves a voltage gain of 23 dB, a noise figure of less than 4 dB, an IIP3 of greater than -6.5 dBm, and an IIP2 of greater than 28 dBm across the entire input band from 54 MHz to 882 MHz.

A CMOS up-conversion mixer with an intermediate frequency (IF) amplifier and local oscillator (LO) buffer is presented for mobile 28-GHz-band 5G dual-conversion transceivers. A balun transformer with improved common-mode rejection ratio characteristics is proposed to improve the LO second-harmonic signal suppression, which is a problem in the up-conversion mixer of the 5G dual-conversion architecture. By applying the proposed balun transformer instead of the conventional one, a common-mode rejection ratio greater than 10 dB can be achieved at the frequencies of the LO second-harmonic leakage signal. An up-conversion mixer with an IF amplifier and LO buffer incorporating the proposed balun transformer was implemented in a 65-nm CMOS process, and it draws a current of 31.4 mA from a 1-V supply voltage. It provides a gain larger than 22.2 dB, a noise figure less than 4.1 dB, a thirdorder output intercept point higher than 4.6 dBm, and an LO second-harmonic leakage signal lower than -55.5 dBm in frequencies ranging from 26.5 GHz to 29.5 GHz. It also exhibits a suppression improvement of the LO second-harmonic leakage signal of approximately 14 dB with respect to an up-conversion mixer with IF amplifier and LO buffer using the conventional balun transformer. The proposed up-mixer with IF amplifier and LO buffer is the first one reported that addresses the 2LO leakage issue and the first demonstration of 2LO leakage signal suppression improvement for a 5G mmWave dual-conversion single-quadrature transmitter.